Series & Analogy — Complete Guide

Table of Contents

1. Reference Chapter: Tools You Must Know by Heart
2. Part A: Number & Alphabet Series
3. Chapter 1: Introduction to Series Questions
4. Chapter 2: Number Series — Arithmetic (Constant / Changing Difference)
5. Chapter 3: Number Series — Geometric (Constant Ratio) and Mixed Series
6. Chapter 4: Number Series — Squares, Cubes, and Offset Series
7. Chapter 5: Number Series — Prime Numbers and Interleaved (Alternating) Series
8. Chapter 6: Number Series — 'Find the Wrong Number' Format
9. Chapter 7: Alphabet Series
10. Chapter 8: Alphanumeric Series
11. Chapter 9: Continuation-Type Series
12. Part B: Analogy
13. Chapter 10: Introduction to Analogy
14. Chapter 11: Number Analogy
15. Chapter 12: Letter / Alphabet Analogy
16. Chapter 13: Word / Meaning Analogy
17. Chapter 14: 'Odd One Out' / Classification Questions
18. Chapter 15: Common Traps Across Series and Analogy
19. Chapter 16: A Step-by-Step Solving Framework for Exam Speed
20. Chapter 17: Quick Revision Cheat-Sheet
21. Full-Length Practice Set (Mixed: Series & Analogy)
22. Consolidated Answer Key — Practice Set

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1. Reference Chapter: Tools You Must Know by Heart

Almost every Series and Analogy question leans on a small set of number facts and the alphabet-position table. Before starting the chapters, memorise the three charts below. Spending ten minutes here saves minutes in every future question — you should be able to recall any square, cube, or letter position in under two seconds during the exam.

1. Alphabet Position Table (Forward and Backward)

Forward position = the letter's normal place from A (A=1 ... Z=26). Backward position = its place counted from Z (Z=1 ... A=26). Backward position = 27 − Forward position. This single formula solves most 'opposite letter' and 'reverse alphabet' questions instantly.

A	B	C	D	E	F	G	H	I	J	K	L	M
1	2	3	4	5	6	7	8	9	10	11	12	13
26	25	24	23	22	21	20	19	18	17	16	15	14

N	O	P	Q	R	S	T	U	V	W	X	Y	Z
14	15	16	17	18	19	20	21	22	23	24	25	26
13	12	11	10	9	8	7	6	5	4	3	2	1

Speed Tip: To find a letter's opposite (mirror) letter quickly: Opposite = 27 − position, then convert back to a letter. Example: opposite of D (4th) is the (27−4)=23rd letter = W.

2. Squares and Cubes of 1 to 30

Series questions frequently hide a square (n²) or cube (n³) pattern, sometimes with a small offset such as n²+1 or n³−2. Recognising these values on sight — without calculating — is the single biggest speed boost in this topic.

n	1	2	3	4	5	6	7	8	9	10
n²	1	4	9	16	25	36	49	64	81	100
n³	1	8	27	64	125	216	343	512	729	1000

n	11	12	13	14	15	16	17	18	19	20
n²	121	144	169	196	225	256	289	324	361	400
n³	1331	1728	2197	2744	3375	4096	4913	5832	6859	8000

n	21	22	23	24	25	26	27	28	29	30
n²	441	484	529	576	625	676	729	784	841	900
n³	9261	10648	12167	13824	15625	17576	19683	21952	24389	27000

3. Prime Numbers up to 100

There are 25 prime numbers below 100. Memorise this list in order — prime-number series and 'is this number prime' checks (used in wrong-number questions) both depend on instant recall.

2	3	5	7	11
13	17	19	23	29
31	37	41	43	47
53	59	61	67	71
73	79	83	89	97

Speed Tip: Quick prime check for a number N (up to 100): N is prime if it is not divisible by 2, 3, 5, or 7 (since 7×7=49 and 11×11=121>100, you only need to test primes up to √N).

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2. Part A: Number & Alphabet Series

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3. Chapter 1: Introduction to Series Questions

A 'series' question gives you a sequence of numbers, letters, or a mix of both, built on a hidden rule. You are asked to do one of three things:

• Find the missing term — one term (usually the last, sometimes a middle one marked with '?') has been removed; find what fits the pattern.
• Find the next term — extend the given sequence by one more step (continuation-type).
• Find the wrong term — every term is shown, but one of them breaks the pattern; identify which one does not belong.

Before solving, always read the instruction line carefully — confusing 'find the next term' with 'find the wrong term' is one of the most common reasons for losing an otherwise easy mark.

The Pattern-Testing Checklist

When a series does not reveal its logic immediately, test the following patterns in this order. Most SSC/RRB series questions are solved within the first four checks.

• Difference pattern — is the difference between consecutive terms constant, or itself increasing/decreasing by a fixed amount?
• Ratio pattern — is each term a fixed multiple (or fraction) of the previous term?
• Alternating / interleaved pattern — do odd positions and even positions follow two separate, simpler rules?
• Squares or cubes — do the terms match n², n³, or a close offset such as n²+1, n³−2?
• Prime numbers — are the terms simply consecutive primes, or primes multiplied/added to something?
• Two-stage / mixed operations — does the rule combine two operations, such as ×2 then +1, or +n then ×2, changing every step?

Common Trap: Do not lock onto the first pattern that fits two terms. Many series look arithmetic for the first two or three terms but switch to a mixed or increasing-difference rule later. Always verify your rule against every given term before applying it to find the answer.

Speed Tip: Write out the differences (or ratios) between consecutive terms in the margin as a mini-series of its own. A pattern that is invisible in the main series often becomes obvious in this 'difference row'.

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4. Chapter 2: Number Series — Arithmetic (Constant / Changing Difference)

An arithmetic series has a common difference between consecutive terms. In the simplest form this difference is constant (e.g., +4 every time). A large share of SSC/RRB questions use a slightly harder version: the difference itself increases or decreases by a fixed amount at every step.

Type 1: Constant Difference

Series: 5, 9, 13, 17, ... — each term is 4 more than the last. This is the most basic pattern and should be the very first thing you check.

Type 2: Increasing or Decreasing Difference

Series: 3, 6, 10, 15, 21, ... — the differences are 3, 4, 5, 6 (increasing by 1 each time). Series: 100, 90, 81, 73, ... — the differences are −10, −9, −8 (decreasing in magnitude by 1 each time, i.e., approaching zero).

Worked Example: Find the missing term: 7, 12, 19, 28, 39, ?

Step 1: Find consecutive differences: 12−7=5, 19−12=7, 28−19=9, 39−28=11.

Step 2: The differences themselves form a series: 5, 7, 9, 11 — increasing by 2 each time.

Step 3: The next difference should be 11+2=13.

Step 4: Add this to the last term: 39+13=52.

Answer: 52

Common Trap: When the difference row itself is not constant, do not stop after finding the first two differences — confirm the difference-of-differences (the second-level pattern) using at least three gaps before predicting the next one.

Speed Tip: If the first difference is small and grows slowly (like +3, +4, +5...), suspect a 'sum of consecutive numbers' or near-square pattern. If differences roughly double, suspect an underlying geometric or squared relationship instead.

Additional Worked Example

Worked Example: Find the missing term: 90, 80, 71, 63, 56, ?

Step 1: Find consecutive differences: 80−90=−10, 71−80=−9, 63−71=−8, 56−63=−7.

Step 2: The differences form their own series: −10, −9, −8, −7 — increasing by 1 (becoming less negative).

Step 3: The next difference should be −7+1 = −6.

Step 4: Add this to the last term: 56+(−6) = 50.

Answer: 50

Practice: Arithmetic Series

Q1. 5, 9, 13, 17, ? (A) 19 (B) 20 (C) 21 (D) 23 Answer: (C) 21. Explanation: Common difference is +4 throughout (5→9→13→17). Next term = 17+4 = 21.

Q2. 2, 5, 8, 11, 14, ? (A) 15 (B) 16 (C) 18 (D) 17 Answer: (D) 17. Explanation: Common difference is +3 (2→5→8→11→14). Next term = 14+3 = 17.

Q3. 50, 45, 40, 35, ? (A) 30 (B) 28 (C) 32 (D) 25 Answer: (A) 30. Explanation: Common difference is −5 throughout. Next term = 35−5 = 30.

Q4. 3, 6, 10, 15, 21, ? (A) 27 (B) 26 (C) 28 (D) 29 Answer: (C) 28. Explanation: Differences: 3, 4, 5, 6 — increasing by 1. Next difference = 7, so 21+7 = 28.

Q5. 100, 90, 81, 73, 66, ? (A) 61 (B) 60 (C) 59 (D) 58 Answer: (B) 60. Explanation: Differences: −10, −9, −8, −7 — increasing by 1 (less negative). Next difference = −6, so 66−6 = 60.

Q6. 7, 12, 19, 28, 39, ? (A) 50 (B) 52 (C) 51 (D) 53 Answer: (B) 52. Explanation: Differences: 5, 7, 9, 11 — increasing by 2. Next difference = 13, so 39+13 = 52.

Q7. 1, 2, 4, 7, 11, 16, ? (A) 21 (B) 23 (C) 22 (D) 20 Answer: (C) 22. Explanation: Differences: 1, 2, 3, 4, 5 — increasing by 1. Next difference = 6, so 16+6 = 22.

Q8. 80, 70, 61, 53, 46, ? (A) 39 (B) 41 (C) 38 (D) 40 Answer: (D) 40. Explanation: Differences: −10, −9, −8, −7 — increasing by 1. Next difference = −6, so 46−6 = 40.

Q9. 6, 11, 17, 24, 32, ? (A) 40 (B) 41 (C) 39 (D) 42 Answer: (B) 41. Explanation: Differences: 5, 6, 7, 8 — increasing by 1. Next difference = 9, so 32+9 = 41.

Q10. 2, 3, 5, 8, 12, 17, ? (A) 22 (B) 24 (C) 23 (D) 21 Answer: (C) 23. Explanation: Differences: 1, 2, 3, 4, 5 — increasing by 1. Next difference = 6, so 17+6 = 23.

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5. Chapter 3: Number Series — Geometric (Constant Ratio) and Mixed Series

A geometric series multiplies (or divides) by a fixed ratio at every step, e.g. 2, 6, 18, 54 (×3 each time). Mixed series combine two operations, such as 'double, then add a growing number', and are common in the moderate-to-hard SSC CGL Tier-I/II range.

Type 1: Constant Ratio

Series: 4, 8, 24, 96, ... — here the ratio itself is not constant (×2, ×3, ×4), which makes it a mixed-ratio series rather than pure geometric. A pure geometric series keeps the same ratio throughout, e.g., 5, 10, 20, 40, 80 (×2 every time).

Type 2: Mixed Multiplication + Addition

Series: 2, 5, 11, 23, 47, ... — each term is double the previous term plus 1 (×2, +1). Such 'multiply-then-adjust' rules are extremely common and must be tested whenever a simple ratio does not fit exactly.

Worked Example: Find the missing term: 6, 9, 15, 27, 51, ?

Step 1: Check ratio: 9/6 = 1.5, 15/9 = 1.67 — not constant, so it is not pure geometric.

Step 2: Check differences instead: 3, 6, 12, 24 — each difference is double the previous one.

Step 3: The next difference should be 24×2 = 48.

Step 4: Add this to the last term: 51+48 = 99.

Answer: 99

Common Trap: Do not give up on a series just because the ratio between terms is not constant. Many 'geometric-looking' series are actually built on a doubling difference (a hidden geometric progression in the difference row), not in the terms themselves.

Speed Tip: If terms grow very fast (roughly doubling or tripling each time), test ×2, ×3 ratios first. If growth is fast but irregular, immediately check whether the differences (not the terms) form a clean geometric progression.

Additional Worked Example

Worked Example: Find the missing term: 4, 12, 36, 108, ?

Step 1: Check the ratio between consecutive terms: 12/4=3, 36/12=3, 108/36=3.

Step 2: The ratio is constant at ×3, confirming a pure geometric series.

Step 3: Apply the same ratio: 108×3 = 324.

Answer: 324

Practice: Geometric and Mixed Series

Q11. 2, 6, 18, 54, ? (A) 160 (B) 162 (C) 164 (D) 168 Answer: (B) 162. Explanation: Each term is ×3 of the previous term (2×3=6, 6×3=18, 18×3=54). Next term = 54×3 = 162.

Q12. 3, 6, 12, 24, ? (A) 46 (B) 48 (C) 50 (D) 44 Answer: (B) 48. Explanation: Each term is ×2 of the previous term. Next term = 24×2 = 48.

Q13. 5, 10, 20, 40, 80, ? (A) 150 (B) 160 (C) 170 (D) 140 Answer: (B) 160. Explanation: Constant ratio ×2 throughout. Next term = 80×2 = 160.

Q14. 4, 8, 24, 96, ? (A) 384 (B) 480 (C) 288 (D) 576 Answer: (B) 480. Explanation: Ratios are ×2, ×3, ×4 (increasing by 1 each time). Next ratio = ×5, so 96×5 = 480.

Q15. 3, 7, 15, 31, 63, ? (A) 125 (B) 126 (C) 127 (D) 128 Answer: (C) 127. Explanation: Rule: ×2, then +1 (3×2+1=7, 7×2+1=15, 15×2+1=31, 31×2+1=63). Next term = 63×2+1 = 127.

Q16. 2, 5, 11, 23, 47, ? (A) 93 (B) 94 (C) 95 (D) 96 Answer: (C) 95. Explanation: Rule: ×2, then +1 throughout (2×2+1=5, 5×2+1=11, 11×2+1=23, 23×2+1=47). Next term = 47×2+1 = 95.

Q17. 1, 3, 9, 27, 81, ? (A) 234 (B) 241 (C) 243 (D) 244 Answer: (C) 243. Explanation: Constant ratio ×3 throughout. Next term = 81×3 = 243.

Q18. 6, 9, 15, 27, 51, ? (A) 93 (B) 96 (C) 99 (D) 102 Answer: (C) 99. Explanation: Differences are 3, 6, 12, 24 — each doubling. Next difference = 48, so 51+48 = 99.

Q19. 8, 4, 2, 1, 0.5, ? (A) 0.2 (B) 0.25 (C) 0.3 (D) 0.35 Answer: (B) 0.25. Explanation: Each term is half the previous term (÷2). Next term = 0.5÷2 = 0.25.

Q20. 10, 13, 19, 31, 55, ? (A) 99 (B) 101 (C) 103 (D) 105 Answer: (C) 103. Explanation: Differences are 3, 6, 12, 24 — each doubling. Next difference = 48, so 55+48 = 103.

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6. Chapter 4: Number Series — Squares, Cubes, and Offset Series

These series are built directly from n², n³, or a small adjustment to them, such as n²+1, n²+2, n³−1, or n³+1. Because you memorised the squares/cubes table in the Reference Chapter, you should now be able to spot these on sight rather than compute them.

Worked Example: Find the missing term: 2, 9, 28, 65, 126, ?

Step 1: Compare with cubes: 1³=1, 2³=8, 3³=27, 4³=64, 5³=125.

Step 2: Each given term is exactly 1 more than the corresponding cube: 1+1=2, 8+1=9, 27+1=28, 64+1=65, 125+1=126.

Step 3: The next term corresponds to 6³+1 = 216+1.

Answer: 217

Common Trap: Do not assume every fast-growing series is geometric. Squares and cubes also grow quickly but at a very specific rate — always test n², n³ (and small offsets) before concluding the series is a pure ratio pattern.

Speed Tip: To check quickly if a term is 'close to a square', find the nearest square from your memorised table and note the difference. If that difference is the same small number (like +1, +2, −1) across several terms, you have found an offset-square series.

Additional Worked Example

Worked Example: Find the missing term: 4, 7, 12, 19, 28, ?

Step 1: Compare with squares: 1²=1, 2²=4, 3²=9, 4²=16, 5²=25.

Step 2: Each given term is exactly 3 more than the corresponding square: 1+3=4, 4+3=7, 9+3=12, 16+3=19, 25+3=28.

Step 3: The next term corresponds to 6²+3 = 36+3.

Answer: 39

Practice: Square and Cube Series

Q21. 1, 4, 9, 16, 25, ? (A) 32 (B) 34 (C) 36 (D) 38 Answer: (C) 36. Explanation: Series of squares: 1², 2², 3², 4², 5². Next term = 6² = 36.

Q22. 2, 5, 10, 17, 26, ? (A) 35 (B) 36 (C) 37 (D) 38 Answer: (C) 37. Explanation: Pattern is n²+1: 1+1, 4+1, 9+1, 16+1, 25+1. Next term = 36+1 = 37.

Q23. 1, 8, 27, 64, 125, ? (A) 196 (B) 210 (C) 216 (D) 225 Answer: (C) 216. Explanation: Series of cubes: 1³, 2³, 3³, 4³, 5³. Next term = 6³ = 216.

Q24. 0, 7, 26, 63, 124, ? (A) 210 (B) 215 (C) 218 (D) 220 Answer: (B) 215. Explanation: Pattern is n³−1: 1−1, 8−1, 27−1, 64−1, 125−1. Next term = 216−1 = 215.

Q25. 3, 6, 11, 18, 27, ? (A) 36 (B) 37 (C) 38 (D) 39 Answer: (C) 38. Explanation: Pattern is n²+2: 1+2, 4+2, 9+2, 16+2, 25+2. Next term = 36+2 = 38.

Q26. 9, 16, 25, 36, ? (A) 47 (B) 48 (C) 49 (D) 50 Answer: (C) 49. Explanation: Consecutive squares from 3²: 3², 4², 5², 6². Next term = 7² = 49.

Q27. 2, 9, 28, 65, 126, ? (A) 215 (B) 216 (C) 217 (D) 218 Answer: (C) 217. Explanation: Pattern is n³+1: 1+1, 8+1, 27+1, 64+1, 125+1. Next term = 216+1 = 217.

Q28. 4, 9, 16, 25, 36, ? (A) 47 (B) 48 (C) 49 (D) 50 Answer: (C) 49. Explanation: Consecutive squares from 2²: 2², 3², 4², 5², 6². Next term = 7² = 49.

Q29. 8, 27, 64, 125, ? (A) 196 (B) 200 (C) 216 (D) 220 Answer: (C) 216. Explanation: Series of cubes from 2³: 2³, 3³, 4³, 5³. Next term = 6³ = 216.

Q30. 5, 13, 29, 53, 85, ? (A) 121 (B) 123 (C) 125 (D) 127 Answer: (C) 125. Explanation: Pattern is (odd number)²+4, using 1,3,5,7,9,11: 1+4=5, 9+4=13, 25+4=29, 49+4=53, 81+4=85. Next: 11²+4 = 121+4 = 125.

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7. Chapter 5: Number Series — Prime Numbers and Interleaved (Alternating) Series

Two distinct ideas share this chapter. Prime-number series are built purely from the sequence of primes (possibly with a simple operation applied). Interleaved series actually contain two separate series woven together — odd positions (1st, 3rd, 5th...) follow one rule, and even positions (2nd, 4th, 6th...) follow a different rule.

Worked Example: Find the missing term: 2, 20, 4, 17, 6, 14, 8, ?

Step 1: Separate the positions: odd positions (1st,3rd,5th,7th) = 2, 4, 6, 8 — increasing by 2.

Step 2: Even positions (2nd,4th,6th) = 20, 17, 14 — decreasing by 3.

Step 3: The missing term is the 8th term, an even position, so continue that sub-series: 14−3 = 11.

Answer: 11

Common Trap: The most common mistake is trying to find one single rule that connects every term in order. If a series refuses to fit any single pattern but alternates between 'looks fine, looks odd', immediately split it into two sub-series (odd positions and even positions) before trying anything else.

Speed Tip: Underline or circle alternate terms lightly as you read the series in the exam — this visually separates the two hidden series and prevents you from mixing their rules.

Additional Worked Example

Worked Example: Find the missing term: 6, 4, 12, 8, 18, 12, 24, ?

Step 1: Separate positions: odd positions (1st,3rd,5th,7th) = 6, 12, 18, 24 — increasing by 6 each time.

Step 2: Even positions (2nd,4th,6th) = 4, 8, 12 — increasing by 4 each time.

Step 3: The missing 8th term is an even position, so continue that sub-series: 12+4 = 16.

Answer: 16

Practice: Prime Number and Interleaved Series

Q31. 2, 3, 5, 7, 11, ? (A) 12 (B) 13 (C) 14 (D) 15 Answer: (B) 13. Explanation: Series of consecutive prime numbers. After 11, the next prime is 13.

Q32. 3, 5, 7, 11, 13, ? (A) 15 (B) 16 (C) 17 (D) 19 Answer: (C) 17. Explanation: Consecutive primes starting from 3. After 13, the next prime is 17.

Q33. 11, 13, 17, 19, 23, ? (A) 27 (B) 29 (C) 31 (D) 25 Answer: (B) 29. Explanation: Consecutive primes. After 23, the next prime is 29.

Q34. 1, 10, 3, 8, 5, 6, 7, ? (A) 2 (B) 3 (C) 4 (D) 5 Answer: (C) 4. Explanation: Odd positions: 1,3,5,7 (increasing by 2). Even positions: 10,8,6,? (decreasing by 2). The 8th term (even position) = 6−2 = 4.

Q35. 2, 20, 4, 17, 6, 14, 8, ? (A) 10 (B) 11 (C) 12 (D) 13 Answer: (B) 11. Explanation: Odd positions: 2,4,6,8 (+2 each). Even positions: 20,17,14,? (−3 each). The 8th term = 14−3 = 11.

Q36. 5, 4, 10, 8, 15, 12, 20, ? (A) 14 (B) 15 (C) 16 (D) 18 Answer: (C) 16. Explanation: Odd positions: 5,10,15,20 (+5 each). Even positions: 4,8,12,? (+4 each). The 8th term = 12+4 = 16.

Q37. 4, 6, 10, 14, 22, ? (A) 24 (B) 26 (C) 28 (D) 30 Answer: (B) 26. Explanation: Each term is double a prime number: 2×2=4, 3×2=6, 5×2=10, 7×2=14, 11×2=22. Next: 13×2=26.

Q38. 3, 9, 6, 15, 9, 21, 12, ? (A) 24 (B) 25 (C) 27 (D) 28 Answer: (C) 27. Explanation: Odd positions: 3,6,9,12 (+3 each). Even positions: 9,15,21,? (+6 each). The 8th term = 21+6 = 27.

Q39. 2, 3, 5, 7, 11, 13, 17, ? (A) 18 (B) 19 (C) 20 (D) 21 Answer: (B) 19. Explanation: Consecutive prime numbers. After 17, the next prime is 19.

Q40. 100, 1, 90, 4, 80, 9, 70, ? (A) 14 (B) 15 (C) 16 (D) 17 Answer: (C) 16. Explanation: Odd positions: 100,90,80,70 (−10 each). Even positions: 1,4,9,? — these are squares 1²,2²,3²,?; the 8th term = 4² = 16.

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8. Chapter 6: Number Series — 'Find the Wrong Number' Format

Here, every term of the series is shown — none are hidden. Exactly one term breaks the underlying rule, and your task is to identify that term (not to calculate what it 'should' be, although working that out is how you find it). Always start by writing out the differences or ratios for the whole series before choosing an answer.

Worked Example: Find the wrong number: 8, 27, 64, 125, 215, 343

Step 1: Compare with cubes: 2³=8, 3³=27, 4³=64, 5³=125, 6³=216, 7³=343.

Step 2: Every term matches its cube except the fifth term: 215 should be 216.

Answer: 215 is the wrong term

Common Trap: Do not stop checking after finding one term that looks 'a bit odd'. Confirm the full pattern using at least four of the remaining terms so that you are certain only one term is wrong, and that you have identified the correct one.

Speed Tip: For wrong-number questions, it is often faster to compute what the correct pattern predicts for every position and compare, rather than trying to 'spot' the odd one by eye — small differences (like 63 vs 64) are easy to miss visually.

Additional Worked Example

Worked Example: Find the wrong term: 4, 6, 10, 18, 32, 66

Step 1: Check the pattern: each term should equal (previous term × 2) minus 2: 4×2−2=6, 6×2−2=10, 10×2−2=18, 18×2−2=34, 34×2−2=66.

Step 2: The given series has 32 in place of 34 at the fifth position.

Answer: 32 is the wrong term (it should be 34)

Practice: Wrong Number in the Series

Q41. Find the wrong term: 3, 6, 9, 14, 15, 18 (A) 6 (B) 9 (C) 14 (D) 18 Answer: (C) 14. Explanation: The series should increase by a constant +3 each time (3,6,9,12,15,18). The term 14 breaks this pattern; it should be 12.

Q42. Find the wrong term: 2, 4, 8, 16, 30, 64 (A) 8 (B) 16 (C) 30 (D) 64 Answer: (C) 30. Explanation: Pattern is ×2 each time (2,4,8,16,32,64). The term 30 is wrong; it should be 32.

Q43. Find the wrong term: 1, 4, 9, 16, 24, 36 (A) 9 (B) 16 (C) 24 (D) 36 Answer: (C) 24. Explanation: These should be consecutive squares (1,4,9,16,25,36). The term 24 is wrong; it should be 25.

Q44. Find the wrong term: 5, 10, 17, 26, 37, 49 (A) 17 (B) 26 (C) 37 (D) 49 Answer: (D) 49. Explanation: Pattern is n²+1 for n=2,3,4,5,6,7: 5,10,17,26,37,50. The term 49 is wrong; it should be 50.

Q45. Find the wrong term: 8, 27, 64, 125, 215, 343 (A) 27 (B) 64 (C) 125 (D) 215 Answer: (D) 215. Explanation: These should be consecutive cubes (8,27,64,125,216,343). The term 215 is wrong; it should be 216.

Q46. Find the wrong term: 10, 14, 20, 29, 38, 50 (A) 14 (B) 20 (C) 29 (D) 38 Answer: (C) 29. Explanation: Differences should increase by 2 each time: +4,+6,+8,+10,+12 (10,14,20,28,38,50). The term 29 is wrong; it should be 28.

Q47. Find the wrong term: 2, 5, 10, 17, 26, 36 (A) 10 (B) 17 (C) 26 (D) 36 Answer: (D) 36. Explanation: Pattern is n²+1 (2,5,10,17,26,37). The term 36 is wrong; it should be 37.

Q48. Find the wrong term: 7, 13, 25, 49, 97, 192 (A) 25 (B) 49 (C) 97 (D) 192 Answer: (D) 192. Explanation: Pattern is ×2−1 each time (7,13,25,49,97,193). The term 192 is wrong; it should be 193.

Q49. Find the wrong term: 4, 6, 9, 13, 16, 20, 25 (A) 6 (B) 9 (C) 13 (D) 16 Answer: (C) 13. Explanation: Differences alternate +2,+3,+3,+4,+4,+5 (4,6,9,12,16,20,25). The term 13 is wrong; it should be 12.

Q50. Find the wrong term: 1, 2, 6, 24, 120, 620 (A) 6 (B) 24 (C) 120 (D) 620 Answer: (D) 620. Explanation: These should be factorials: 1!,2!,3!,4!,5!,6! = 1,2,6,24,120,720. The term 620 is wrong; it should be 720.

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9. Chapter 7: Alphabet Series

Alphabet series apply the same difference/ratio logic to letter positions instead of numbers. Convert each letter to its position number (using the Reference Chapter table) to work exactly as you would with a number series, then convert your final answer back into a letter.

Single-Letter Series

Series: A, C, E, G, ... — positions 1,3,5,7 — skipping one letter each time (+2). Convert to numbers, find the pattern, then convert back.

Series of Letter-Groups

Series: AB, DE, GH, JK, ... — each group's starting letter jumps by 3 positions (A→D→G→J), and the group always contains two consecutive letters.

Worked Example: Find the missing term: M, O, R, V, ?

Step 1: Convert to positions: M=13, O=15, R=18, V=22.

Step 2: Find differences: 15−13=2, 18−15=3, 22−18=4 — increasing by 1 each time.

Step 3: Next difference = 5, so next position = 22+5 = 27.

Step 4: There are only 26 letters, so wrap around: 27−26 = 1, which is the letter A.

Answer: A

Common Trap: Alphabet series that go past Z require you to wrap around: position 27 becomes A (position 1), position 28 becomes B (position 2), and so on — subtract 26 from any position greater than 26.

Speed Tip: Always work in numbers, not letters — mental arithmetic on '13, 15, 18, 22' is far more reliable under time pressure than tracking letters directly, especially past M where letter-to-number conversion slows down.

Additional Worked Example

Worked Example: Find the missing term: D, G, K, P, ?

Step 1: Convert to positions: D=4, G=7, K=11, P=16.

Step 2: Find differences: 7−4=3, 11−7=4, 16−11=5 — increasing by 1 each time.

Step 3: Next difference = 6, so next position = 16+6 = 22, which is the letter V.

Answer: V

Practice: Alphabet Series

Q51. A, C, E, G, ? (A) H (B) I (C) J (D) K Answer: (B) I. Explanation: Positions 1,3,5,7 — skip one letter (+2) each time. Next position = 9 = I.

Q52. B, D, F, H, ? (A) I (B) J (C) K (D) L Answer: (B) J. Explanation: Positions 2,4,6,8 — skip one letter (+2) each time. Next position = 10 = J.

Q53. Z, X, V, T, ? (A) Q (B) R (C) S (D) P Answer: (B) R. Explanation: Positions 26,24,22,20 — decreasing by 2 (skip one letter backward). Next position = 18 = R.

Q54. AB, DE, GH, JK, ? (A) LM (B) MN (C) NO (D) MO Answer: (B) MN. Explanation: Starting letters jump +3 each time (A,D,G,J,M), each group is two consecutive letters. Next group = MN.

Q55. A, D, I, P, ? (A) W (B) X (C) Y (D) Z Answer: (C) Y. Explanation: Positions 1,4,9,16 — these are perfect squares (1²,2²,3²,4²). Next position = 5² = 25 = Y.

Q56. Y, W, U, S, ? (A) P (B) Q (C) R (D) O Answer: (B) Q. Explanation: Positions 25,23,21,19 — decreasing by 2 each time. Next position = 17 = Q.

Q57. CAT, FDW, IGZ, ? (A) LJC (B) LJD (C) MJC (D) LKC Answer: (A) LJC. Explanation: Each letter of the group moves forward by 3 positions (wrapping past Z). C→F→I→L, A→D→G→J, T→W→Z→C (wraps). Next group = LJC.

Q58. AZ, BY, CX, DW, ? (A) EV (B) EU (C) DV (D) FV Answer: (A) EV. Explanation: First letter moves forward by 1 (A,B,C,D,E); second letter moves backward by 1 (Z,Y,X,W,V). Next group = EV.

Q59. M, O, R, V, ? (A) Z (B) B (C) A (D) C Answer: (C) A. Explanation: Positions 13,15,18,22 — differences 2,3,4, increasing by 1. Next difference = 5, so position = 22+5 = 27, which wraps around (27−26=1) to the letter A.

Q60. J, L, O, S, ? (A) W (B) X (C) Y (D) V Answer: (B) X. Explanation: Positions 10,12,15,19 — differences 2,3,4, increasing by 1. Next difference = 5, so position = 24 = X.

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10. Chapter 8: Alphanumeric Series

Alphanumeric series mix letters, numbers, and sometimes symbols in one sequence. Two extra question formats are common here: 'how many such pairs satisfy a condition' (a counting question) and 'which element is Nth from the left/right' (a positional question). Both require careful, patient counting rather than pattern-spotting.

Worked Example: How many pairs have the number equal to the alphabetical position of the letter? A1, B3, C5, G7, D9, E11, F8

Step 1: Check A1: A is position 1, number is 1 — matches.

Step 2: Check B3: B is position 2, number is 3 — no match.

Step 3: Check C5: C is position 3, number is 5 — no match.

Step 4: Check G7: G is position 7, number is 7 — matches.

Step 5: Check D9, E11, F8: positions 4, 5, 6 — none match their numbers.

Step 6: Count of matching pairs = 2 (A1 and G7).

Answer: 2

Common Trap: In alphanumeric 'how many pairs' questions, always re-read the exact condition (equal to, double of, sum of digits equal to, etc.) before scanning — applying the wrong condition to a correctly-scanned list is the single biggest source of error here.

Speed Tip: For 'Nth from left/right' questions, number every element above the series 1, 2, 3... from the left as you read it once; then for 'from the right', use (Total elements − N + 1) instead of recounting from scratch.

Additional Worked Example

Worked Example: Find the missing term: C3, F6, I12, L24, ?

Step 1: Letters: C, F, I, L — each jumps forward by 3 positions (skip two letters).

Step 2: Numbers: 3, 6, 12, 24 — each doubles the previous number.

Step 3: Next letter after L (jump +3) is O; next number after 24 (×2) is 48.

Answer: O48

Practice: Alphanumeric Series

Q61. A1, C4, E9, G16, ? (A) I25 (B) I24 (C) H25 (D) I20 Answer: (A) I25. Explanation: Letters skip by 2 (A,C,E,G,I); numbers are perfect squares (1,4,9,16,25). Next term = I25.

Q62. Z26, Y25, X24, ? (A) W23 (B) W24 (C) V23 (D) W22 Answer: (A) W23. Explanation: Both letter and number decrease together by 1. Next term = W23.

Q63. B2, D4, F6, H8, ? (A) J10 (B) I10 (C) J9 (D) K10 Answer: (A) J10. Explanation: Letters skip by 2 (B,D,F,H,J); numbers increase by 2 (2,4,6,8,10). Next term = J10.

Q64. How many pairs have the number equal to the alphabetical position of the letter? A1, B3, C5, D9, E11, F8, G7 (A) 1 (B) 2 (C) 3 (D) 4 Answer: (B) 2. Explanation: A(1)=1 matches; G(7)=7 matches. B,C,D,E,F do not match their numbers. Total = 2.

Q65. What is the 4th element from the right end? 7, B, $, 3, K, %, 9, M, &, 2, T (A) 2 (B) & (C) M (D) 9 Answer: (C) M. Explanation: Counting from the right: 1st=T, 2nd=2, 3rd=&, 4th=M.

Q66. How many symbols are there in: R, 5, K, #, 9, T, &, 3, M? (A) 1 (B) 2 (C) 3 (D) 4 Answer: (B) 2. Explanation: The elements are R, 5, K, #, 9, T, &, 3, M. Only # and & are symbols, so there are 2 symbols.

Q67. A2, C6, E12, G20, ? (A) I28 (B) I30 (C) H30 (D) I32 Answer: (B) I30. Explanation: Numbers follow n(n+1): 1×2=2, 2×3=6, 3×4=12, 4×5=20; letters skip by 2 (A,C,E,G,I). Next number = 5×6=30, so answer is I30.

Q68. 5D, 10H, 15L, 20P, ? (A) 25T (B) 24T (C) 25S (D) 25U Answer: (A) 25T. Explanation: Numbers increase by 5 (5,10,15,20,25); letters skip by 3 (D,H,L,P,T). Next term = 25T.

Q69. 4B7, 8D11, 12F15, ? (A) 16H19 (B) 16G19 (C) 16H18 (D) 15H19 Answer: (A) 16H19. Explanation: First number +4 (4,8,12,16); letter skips by 2 (B,D,F,H); last number +4 (7,11,15,19). Next term = 16H19.

Q70. B2D, D4F, F6H, H8J, ? (A) J10L (B) I10L (C) J10K (D) J12L Answer: (A) J10L. Explanation: Outer letters skip by 2 each group (B-D, D-F, F-H, H-J, next J-L); middle number increases by 2 (2,4,6,8,10). Next term = J10L.

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11. Chapter 9: Continuation-Type Series

A partial sequence is given, usually as small groups (of letters, numbers, or both), and you must extend it to find the next group. The logic is identical to earlier chapters — the only difference is that the 'terms' are themselves short groups rather than single letters or numbers.

Worked Example: Find the next group: AB, DE, GH, ?

Step 1: Look at the first letter of each group: A, D, G — increasing by 3 positions.

Step 2: Look at the structure: each group is two consecutive letters.

Step 3: The next starting letter is G+3 = J, and its group is JK.

Answer: JK

Common Trap: Do not assume the internal structure of each group (e.g., 'always two consecutive letters') will definitely continue — quickly verify it holds for at least two of the given groups before extending the pattern.

Speed Tip: Treat each group like a single 'super-term' — find the pattern between groups first (usually on the first letter or first digit), then apply the group's internal rule (like +1 letter) separately.

Additional Worked Example

Worked Example: Find the next group: 2A, 4C, 8E, ?

Step 1: Numbers: 2, 4, 8 — doubling each time (×2), so the next number is 16.

Step 2: Letters: A, C, E — skipping one letter each time (+2), so the next letter is G.

Answer: 16G

Practice: Continuation-Type Series

Q71. AB, DE, GH, ? (A) JK (B) IJ (C) KL (D) JL Answer: (A) JK. Explanation: Starting letters jump by 3 (A,D,G,J); each group is two consecutive letters. Next group = JK.

Q72. CD, GH, KL, ? (A) MN (B) NO (C) OP (D) PQ Answer: (C) OP. Explanation: Starting letters jump by 4 (C,G,K,O); each group is two consecutive letters. Next group = OP.

Q73. AZ, CX, EV, ? (A) GT (B) FT (C) GU (D) HT Answer: (A) GT. Explanation: First letter moves forward by 2 (A,C,E,G); second letter moves backward by 2 (Z,X,V,T). Next group = GT.

Q74. 12, 23, 34, ? (A) 44 (B) 45 (C) 46 (D) 43 Answer: (B) 45. Explanation: Each term increases by 11 (12+11=23, 23+11=34). Next term = 34+11 = 45.

Q75. XY, VW, TU, ? (A) RS (B) QR (C) SR (D) RQ Answer: (A) RS. Explanation: Each letter moves backward by 2 positions (X→V→T→R, Y→W→U→S). Next group = RS.

Q76. AB, BD, DG, ? (A) GJ (B) GK (C) HK (D) GL Answer: (B) GK. Explanation: The second letter of each group becomes the first letter of the next group, and the gap between the two letters increases by 1 each time: A(1)-B(2) gap1; B(2)-D(4) gap2; D(4)-G(7) gap3. The next group starts at G(7) with gap 4: G(7)-K(11). Next group = GK.

Q77. 5A, 10B, 20C, ? (A) 30D (B) 35D (C) 40D (D) 40E Answer: (C) 40D. Explanation: Number doubles each time (5,10,20,40); letter moves forward by 1 (A,B,C,D). Next group = 40D.

Q78. PQ, RS, TU, ? (A) VW (B) UV (C) WX (D) VX Answer: (A) VW. Explanation: Starting letters jump by 2 (P,R,T,V); each group is two consecutive letters. Next group = VW.

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12. Part B: Analogy

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13. Chapter 10: Introduction to Analogy

An analogy question gives you one pair of items connected by a specific, definable relationship (for example, 'Doctor is to Hospital' — a person works at that place). You must either apply the same relationship to a new item to complete a second pair, or pick the option-pair among four choices that shares the exact same relationship as the given pair.

Two Common Question Formats

• Complete the pair: 'Doctor : Hospital :: Teacher : ?' — find the single word that completes the second pair the same way.
• Classification by relationship: 'Select the pair that has the same relationship as: Pen : Write' from four answer-pairs — only one option shares the identical relationship type.

How to Name the Relationship

Before looking at the options, put the relationship into your own short phrase: 'is used to', 'is a type of', 'is the young one of', 'is a part of', 'produces', 'is opposite of'. Naming it precisely prevents you from being misled by an option that merely 'sounds related' but uses a different logical connector.

Common Trap: A very common trap is a distractor option that is topically related but uses a different relationship. For example, given 'Doctor : Stethoscope' (worker : tool), an option like 'Hospital : Doctor' is topically connected but is NOT the same worker-to-tool relationship.

Speed Tip: Say the relationship as a full sentence using both words: 'A Doctor uses a Stethoscope.' Then test each option in the exact same sentence structure — the correct option is the one where the sentence still makes logical sense.

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14. Chapter 11: Number Analogy

Number analogies connect two numbers through an arithmetic operation: squaring, cubing, multiplying/dividing by a constant, reversing digits, or summing digits. Identify the operation on the first pair, then apply the identical operation to the second pair.

Worked Example: 4 : 16 :: 5 : ?

Step 1: Identify the relationship in the first pair: 16 = 4² (the second number is the square of the first).

Step 2: Apply the same rule to the second pair: 5² = 25.

Answer: 25

Common Trap: When two operations could both explain the first pair (e.g., 4:16 could be ×4 or squared, since 4×4=16 either way), check which operation still works consistently when you test it against the answer options — pick the option supported by the more 'natural' or commonly tested relationship (squares/cubes are far more common than large arbitrary multiples in this section).

Speed Tip: Always try, in order: multiply/divide by a constant, square/cube (or square root/cube root), digit reversal, and digit sum — these four cover the vast majority of number analogies in SSC/RRB exams.

Additional Worked Example

Worked Example: 18 : 9 :: 30 : ?

Step 1: Identify the relationship: 9 is half of 18 (18÷2=9).

Step 2: Apply the same rule to the second pair: 30÷2 = 15.

Answer: 15

Practice: Number Analogy

Q79. 4 : 16 :: 5 : ? (A) 20 (B) 25 (C) 30 (D) 10 Answer: (B) 25. Explanation: 16 is the square of 4. Applying the same rule, the square of 5 is 25.

Q80. 6 : 36 :: 9 : ? (A) 72 (B) 81 (C) 90 (D) 99 Answer: (B) 81. Explanation: 36 is the square of 6. The square of 9 is 81.

Q81. 3 : 27 :: 4 : ? (A) 48 (B) 56 (C) 64 (D) 72 Answer: (C) 64. Explanation: 27 is the cube of 3. The cube of 4 is 64.

Q82. 8 : 2 :: 27 : ? (A) 2 (B) 3 (C) 4 (D) 9 Answer: (B) 3. Explanation: 2 is the cube root of 8. The cube root of 27 is 3.

Q83. 12 : 6 :: 20 : ? (A) 8 (B) 9 (C) 10 (D) 11 Answer: (C) 10. Explanation: 6 is half of 12. Half of 20 is 10.

Q84. 7 : 56 :: 9 : ? (A) 63 (B) 72 (C) 81 (D) 90 Answer: (B) 72. Explanation: 56 = 7×8 (multiply by 8). 9×8 = 72.

Q85. 15 : 5 :: 24 : ? (A) 6 (B) 7 (C) 8 (D) 9 Answer: (C) 8. Explanation: 5 = 15÷3 (divide by 3). 24÷3 = 8.

Q86. 23 : 32 :: 45 : ? (A) 52 (B) 54 (C) 56 (D) 45 Answer: (B) 54. Explanation: 32 is 23 with its digits reversed. Reversing the digits of 45 gives 54.

Q87. 13 : 4 :: 27 : ? (A) 8 (B) 9 (C) 10 (D) 7 Answer: (B) 9. Explanation: 4 is the digit sum of 13 (1+3=4). The digit sum of 27 is 2+7=9.

Q88. 6 : 11 :: 9 : ? (A) 16 (B) 17 (C) 18 (D) 19 Answer: (B) 17. Explanation: 11 = 6×2−1. Applying the same rule: 9×2−1 = 17.

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15. Chapter 12: Letter / Alphabet Analogy

Letter analogies connect two letter-groups through position shifts (each letter moves forward/backward by a fixed amount), reversal of letters, opposite-letter pairing, or a mix of these applied consistently across all letters in the group.

Worked Example: CAT : FDW :: DOG : ?

Step 1: Convert to positions: C(3),A(1),T(20) → F(6),D(4),W(23).

Step 2: Each letter has moved forward by exactly 3 positions (3→6, 1→4, 20→23).

Step 3: Apply the same +3 shift to D,O,G: D(4)→G(7), O(15)→R(18), G(7)→J(10).

Answer: GRJ

Common Trap: Always verify the shift on every letter of the group, not just the first one — some questions apply a different shift to each letter position within the group (e.g., first letter +1, second letter +2, third letter +3) rather than one uniform shift.

Speed Tip: For 'opposite letter' analogies, use the Reference Chapter formula (Opposite position = 27 − position) rather than trying to count backward from Z each time — it is faster and eliminates counting errors.

Additional Worked Example

Worked Example: FISH : GJTI :: BIRD : ?

Step 1: Convert to positions: F(6),I(9),S(19),H(8) → G(7),J(10),T(20),I(9).

Step 2: Every letter has moved forward by exactly 1 position.

Step 3: Apply the same +1 shift to B,I,R,D: B(2)→C, I(9)→J, R(18)→S, D(4)→E.

Answer: CJSE

Practice: Letter Analogy

Q89. AC : BD :: EG : ? (A) FH (B) FG (C) EH (D) GH Answer: (A) FH. Explanation: Each letter in the pair moves forward by 1 (A→B, C→D). Applying the same shift: E→F, G→H, giving FH.

Q90. CAT : FDW :: DOG : ? (A) GRJ (B) GRI (C) HRJ (D) GQJ Answer: (A) GRJ. Explanation: Every letter shifts forward by 3 positions (C→F, A→D, T→W). Applying the same shift to D,O,G gives G,R,J.

Q91. MAN : OCP :: BAT : ? (A) DCV (B) DCU (C) ECV (D) DBV Answer: (A) DCV. Explanation: Every letter shifts forward by 2 positions (M→O, A→C, N→P). Applying the same shift to B,A,T gives D,C,V.

Q92. ABC : CBA :: DEF : ? (A) FED (B) FDE (C) EFD (D) DFE Answer: (A) FED. Explanation: The second group is the first group's letters written in reverse order. Reversing DEF gives FED.

Q93. PRT : QSU :: BDF : ? (A) CEG (B) CDF (C) CEF (D) BEG Answer: (A) CEG. Explanation: Every letter shifts forward by 1 position (P→Q, R→S, T→U). Applying the same shift to B,D,F gives C,E,G.

Q94. JKL : MNO :: PQR : ? (A) STU (B) SRU (C) STV (D) RTU Answer: (A) STU. Explanation: Every letter shifts forward by 3 positions (J→M, K→N, L→O). Applying the same shift to P,Q,R gives S,T,U.

Q95. Z : A :: Y : ? (A) B (B) C (C) X (D) A Answer: (A) B. Explanation: Z and A are opposite letters (positions 26 and 1; 27−26=1). Y is position 25; its opposite is 27−25=2, which is B.

Q96. BAT : 23 :: CAT : ? (A) 22 (B) 23 (C) 24 (D) 25 Answer: (C) 24. Explanation: 23 is the sum of the alphabet positions of B,A,T (2+1+20=23). The sum for C,A,T is 3+1+20=24.

Q97. DOG : 26 :: CAT : ? (A) 22 (B) 23 (C) 24 (D) 25 Answer: (C) 24. Explanation: 26 is the sum of the positions of D,O,G (4+15+7=26). The sum for C,A,T is 3+1+20=24.

Q98. BD : YW :: CF : ? (A) XU (B) UX (C) VX (D) XW Answer: (A) XU. Explanation: Each letter is replaced by its opposite letter (27−position): B(2)→Y(25), D(4)→W(23). Applying the same rule: C(3)→X(24), F(6)→U(21), giving XU.

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16. Chapter 13: Word / Meaning Analogy

These analogies are based on meaning rather than letters or numbers. The relationship is usually one of a small set of standard types tested repeatedly in SSC/RRB exams:

• Worker : Tool — e.g., Carpenter : Saw
• Worker : Workplace — e.g., Teacher : School
• Part : Whole — e.g., Petal : Flower
• Object : Category — e.g., Rose : Flower
• Cause : Effect — e.g., Fire : Burn
• Animal : Young One — e.g., Dog : Puppy
• Instrument : Measures — e.g., Thermometer : Temperature

Worked Example: Carpenter : Wood :: Blacksmith : ?

Step 1: Name the relationship: a Carpenter's main raw material is Wood.

Step 2: Apply the same relationship: a Blacksmith's main raw material is Iron.

Answer: Iron

Common Trap: Watch for options that name a tool instead of a raw material, or a workplace instead of a product — read the exact relationship type from the given pair before scanning options, since word analogies offer many 'plausible but wrong' choices.

Speed Tip: If two options both seem related, restate the given pair's relationship as precisely as possible (e.g., 'is made mainly of' rather than just 'is connected to') — precision eliminates the almost-right distractor.

Additional Worked Example

Worked Example: Barber : Scissors :: Farmer : ?

Step 1: Name the relationship: a Barber's main working tool is Scissors (worker : tool).

Step 2: Apply the same relationship: a Farmer's main working tool is a Plough.

Answer: Plough

Practice: Word / Meaning Analogy

Q99. Doctor : Hospital :: Teacher : ? (A) Classroom (B) School (C) Book (D) Student Answer: (B) School. Explanation: A Doctor's workplace is a Hospital; a Teacher's workplace is a School (Classroom is only a room within it).

Q100. Pen : Write :: Knife : ? (A) Sharp (B) Cut (C) Kitchen (D) Blade Answer: (B) Cut. Explanation: A Pen is used to Write; a Knife is used to Cut.

Q101. Bird : Nest :: Man : ? (A) Family (B) House (C) City (D) Room Answer: (B) House. Explanation: A Bird lives in a Nest; a Man lives in a House.

Q102. Fish : Water :: Bird : ? (A) Nest (B) Sky (C) Air (D) Tree Answer: (C) Air. Explanation: A Fish lives in the medium of Water; a Bird lives/flies in the medium of Air.

Q103. Cow : Calf :: Dog : ? (A) Kitten (B) Puppy (C) Cub (D) Foal Answer: (B) Puppy. Explanation: A Calf is the young one of a Cow; a Puppy is the young one of a Dog.

Q104. Flower : Petal :: Book : ? (A) Page (B) Cover (C) Author (D) Library Answer: (A) Page. Explanation: A Petal is a part of a Flower; a Page is a part of a Book.

Q105. Carpenter : Wood :: Blacksmith : ? (A) Iron (B) Fire (C) Hammer (D) Shop Answer: (A) Iron. Explanation: A Carpenter's main raw material is Wood; a Blacksmith's main raw material is Iron.

Q106. Thermometer : Temperature :: Speedometer : ? (A) Distance (B) Speed (C) Time (D) Direction Answer: (B) Speed. Explanation: A Thermometer measures Temperature; a Speedometer measures Speed.

Q107. Tailor : Clothes :: Cobbler : ? (A) Wood (B) Shoes (C) Cloth (D) Leather Answer: (B) Shoes. Explanation: A Tailor makes Clothes; a Cobbler makes Shoes.

Q108. Author : Book :: Sculptor : ? (A) Stone (B) Statue (C) Chisel (D) Museum Answer: (B) Statue. Explanation: An Author creates a Book; a Sculptor creates a Statue (Stone and Chisel are raw material/tool, not the finished product).

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17. Chapter 14: 'Odd One Out' / Classification Questions

These questions give four items and ask which one does not belong. The skill is identical to analogy: identify the relationship or category shared by three of the items, and the fourth (which does not fit) is the answer.

Worked Example: Which does not belong: Apple, Mango, Potato, Banana?

Step 1: Three items (Apple, Mango, Banana) are fruits.

Step 2: Potato is a vegetable, not a fruit.

Answer: Potato

Common Trap: Watch for classification traps based on grammar or superficial features (e.g., spelling length, first letter) rather than real category membership — always classify by meaning first.

Speed Tip: If numbers are involved, quickly test: is each number prime? a perfect square? a perfect cube? odd/even? divisible by a small number like 3? One of these checks usually isolates the odd one instantly.

Practice: Odd One Out

Q109. Find the odd one out. (A) Triangle (B) Square (C) Circle (D) Cube Answer: (D) Cube. Explanation: Triangle, Square, and Circle are 2-D (flat) shapes; a Cube is a 3-D solid.

Q110. Find the odd one out. (A) Apple (B) Mango (C) Potato (D) Banana Answer: (C) Potato. Explanation: Apple, Mango, and Banana are fruits; Potato is a vegetable.

Q111. Find the odd one out. (A) 9 (B) 16 (C) 25 (D) 30 Answer: (D) 30. Explanation: 9, 16, and 25 are perfect squares (3², 4², 5²); 30 is not a perfect square.

Q112. Find the odd one out. (A) Delhi (B) Mumbai (C) Kolkata (D) India Answer: (D) India. Explanation: Delhi, Mumbai, and Kolkata are cities; India is a country, not a city.

Q113. Find the odd one out. (A) 2 (B) 3 (C) 9 (D) 7 Answer: (C) 9. Explanation: 2, 3, and 7 are prime numbers; 9 is not prime (9 = 3×3).

Q114. Find the odd one out. (A) ABC (B) DEF (C) GHI (D) JKM Answer: (D) JKM. Explanation: ABC, DEF, and GHI are each three consecutive letters; JKM skips L and breaks the consecutive pattern.

Q115. Find the odd one out. (A) 16 (B) 25 (C) 36 (D) 40 Answer: (D) 40. Explanation: 16, 25, and 36 are perfect squares (4², 5², 6²); 40 is not a perfect square.

Q116. Find the odd one out. (A) Cat (B) Dog (C) Lion (D) Table Answer: (D) Table. Explanation: Cat, Dog, and Lion are animals; Table is a piece of furniture.

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18. Chapter 15: Common Traps Across Series and Analogy

The four errors below account for the large majority of mistakes made on this topic in the exam hall. Reviewing them just before your exam is one of the highest-value five minutes you can spend.

Trap 1: Locking onto a single-operation pattern too early

Seeing the first two terms fit '+3' does not guarantee the whole series is constant-difference. Always check at least three or four gaps/ratios before committing, especially once numbers start growing unevenly.

Trap 2: Missing an alternating (interleaved) pattern

If no single rule fits all terms in order, but every other term looks 'reasonable', split the series into odd-position and even-position sub-series before giving up.

Trap 3: Confusing 'next term' with 'wrong term' instructions

These two instructions require different approaches: 'next term' means extend the pattern; 'wrong term' means every value is already given and one breaks the rule. Misreading the instruction leads you to solve the wrong question entirely, even if your arithmetic is correct.

Trap 4: Ignoring letter-value vs. number-value distinctions in alphanumeric series

In a mixed letter-number sequence, a rule that applies to the number part (like doubling) usually does not simultaneously apply to the letter's alphabet position — treat each 'lane' (letters, numbers, symbols) with its own separate rule unless the question explicitly links them (e.g., 'letter's position equals the number').

Common Trap: When in genuine doubt between two options that both seem to fit a plausible rule, choose the option that keeps the rule simplest and most consistent across ALL given terms — exam-setters strongly prefer patterns with a single, clean, repeatable rule.

Speed Tip: Keep a fixed personal checklist (from Chapter 1) and always run through it in the same order. Speed comes from not re-deciding your approach every question, not from skipping steps.

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19. Chapter 16: A Step-by-Step Solving Framework for Exam Speed

Use this fixed sequence on every Series or Analogy question. With practice, most questions will be solved within the first two or three steps, and this framework should take under 30 seconds per question in the exam.

• Read the instruction line first — 'next term', 'missing term', or 'wrong term'? For analogy — 'complete the pair' or 'choose the matching pair'?
• Convert letters to numbers (position table) if the series/analogy involves letters, so you are always working with numbers.
• Write the difference row (or ratio row) between consecutive terms — this reveals most arithmetic and mixed patterns immediately.
• If no clean pattern appears, check squares, cubes, and primes against your memorised Reference Chapter tables.
• If terms alternate between 'fits' and 'doesn't fit', split into odd-position and even-position sub-series.
• For analogy, state the relationship as a full sentence using both words, then test it against every option using the identical sentence structure.
• Before marking your final answer, verify your rule against every given term (not just the first two) — this single habit eliminates most careless errors.

Speed Tip: If you cannot find any pattern within about 20–25 seconds, mark the question for review and move on — in a timed section, one stuck question should never cost you three easy ones later in the paper.

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20. Chapter 17: Quick Revision Cheat-Sheet

Use this single table to revise every pattern type covered in this book in the last few minutes before your exam. For each row, ask 'does this fit?' in the order given.

Pattern	How to Recognise It	Example
Constant difference	Same gap between every pair of consecutive terms	5, 9, 13, 17 (+4 each)
Changing difference	The gap itself increases/decreases by a fixed amount	3, 6, 10, 15 (+3,+4,+5)
Constant ratio	Same multiplier between every pair of terms	5, 10, 20, 40 (×2 each)
Mixed multiply+add	Ratio not constant, but a ×n then +k rule repeats	2, 5, 11, 23 (×2,+1)
Square series	Terms match n² or n²+k for a fixed k	2, 5, 10, 17 (n²+1)
Cube series	Terms match n³ or n³+k for a fixed k	2, 9, 28, 65 (n³+1)
Prime series	Terms are consecutive prime numbers	2, 3, 5, 7, 11, 13
Interleaved series	Odd and even positions follow two separate rules	2,20,4,17,6,14 (two series)
Wrong-number format	All terms shown; one breaks an otherwise clean rule	8,27,64,125,215,343 (215 wrong)
Alphabet series	Convert letters to positions, then apply number rules	A, D, I, P (n² positions)
Alphanumeric series	Letters and numbers each follow their own separate rule	A1, C4, E9, G16
Continuation series	Groups (not single terms) follow the pattern	AB, DE, GH, JK
Number analogy	One arithmetic operation links each pair	4:16 :: 5:25 (square)
Letter analogy	A consistent position-shift or reversal links each pair	CAT:FDW :: DOG:GRJ (+3 shift)
Word analogy	A fixed real-world relationship links each pair	Doctor:Hospital :: Teacher:School

Speed Tip: In the exam, do not try to recall this whole table from memory question by question. Instead, run the Chapter 1 checklist in order — this cheat-sheet is only for your final revision pass, to make sure no pattern type feels unfamiliar on exam day.

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21. Full-Length Practice Set (Mixed: Series & Analogy)

This set mixes every question type covered in the book, in exam order and difficulty. Solve the full set under timed conditions (aim for under 20 minutes), then check your answers against the consolidated Answer Key with reasoning that follows.

PS1. 2, 6, 12, 20, 30, ? (A) 36 (B) 40 (C) 42 (D) 44

PS2. 11, 13, 17, 19, 23, 29, ? (A) 30 (B) 31 (C) 33 (D) 35

PS3. 7, 14, 28, 56, ? (A) 102 (B) 108 (C) 112 (D) 118

PS4. 1, 1, 2, 3, 5, 8, ? (A) 11 (B) 12 (C) 13 (D) 14

PS5. 25, 24, 22, 19, 15, ? (A) 9 (B) 10 (C) 11 (D) 12

PS6. A, E, I, M, Q, ? (A) T (B) U (C) V (D) S

PS7. BZ, DX, FV, ? (A) HT (B) GT (C) HU (D) IT

PS8. 5, 10, 20, 40, ? (A) 60 (B) 70 (C) 80 (D) 90

PS9. 3, 10, 29, 66, 127, ? (A) 212 (B) 216 (C) 218 (D) 220

PS10. 8, 12, 9, 13, 10, 14, ? (A) 10 (B) 11 (C) 12 (D) 15

PS11. 4 : 20 :: 6 : ? (A) 36 (B) 40 (C) 42 (D) 48

PS12. 9 : 81 :: 11 : ? (A) 99 (B) 110 (C) 121 (D) 132

PS13. CAT : 24 :: DOG : ? (A) 24 (B) 25 (C) 26 (D) 27

PS14. Painter : Canvas :: Writer : ? (A) Pen (B) Paper (C) Book (D) Ink

PS15. Find the odd one out. (A) Rose (B) Lily (C) Cactus (D) Jasmine

PS16. Find the wrong term: 2, 4, 8, 16, 30, 64 (A) 8 (B) 16 (C) 30 (D) 64

PS17. 6, 9, 15, 24, 39, ? (A) 57 (B) 60 (C) 63 (D) 66

PS18. Z, W, T, Q, ? (A) M (B) N (C) O (D) P

PS19. A1, B4, C9, D16, ? (A) E20 (B) E24 (C) E25 (D) D25

PS20. Wood : Furniture :: Cotton : ? (A) Cloth (B) Thread (C) Field (D) Fibre

PS21. Find the odd one out. (A) 121 (B) 144 (C) 169 (D) 150

PS22. 1, 3, 7, 15, 31, ? (A) 61 (B) 62 (C) 63 (D) 64

PS23. Kilogram : Weight :: Metre : ? (A) Length (B) Area (C) Volume (D) Speed

PS24. Find the wrong term: 3, 8, 15, 24, 35, 48, 64 (A) 15 (B) 24 (C) 48 (D) 64

PS25. MNO, PQR, STU, ? (A) VWX (B) UVW (C) WXY (D) VXY

PS26. Thief : Steal :: Judge : ? (A) Punish (B) Judge (C) Court (D) Law

PS27. 16 : 4 :: 81 : ? (A) 8 (B) 9 (C) 10 (D) 27

PS28. J, M, P, S, ? (A) U (B) V (C) W (D) X

PS29. 2, 3, 5, 9, 17, ? (A) 31 (B) 32 (C) 33 (D) 34

PS30. Bee : Hive :: Spider : ? (A) Web (B) Insect (C) Leg (D) Silk

PS31. Find the wrong term: 5, 10, 17, 26, 38, 50 (A) 10 (B) 17 (C) 26 (D) 38

PS32. P, S, W, ? (A) A (B) B (C) C (D) D

PS33. Locksmith : Key :: Author : ? (A) Book (B) Pen (C) Idea (D) Library

PS34. 3, 4, 8, 17, 33, ? (A) 56 (B) 58 (C) 60 (D) 62

PS35. Find the odd one out. (A) March (B) May (C) August (D) Tuesday

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22. Consolidated Answer Key — Practice Set

Q.No	Answer	Reasoning
PS1	C) 42	Pattern is n(n+1): 1×2,2×3,3×4,4×5,5×6,6×7=42.
PS2	B) 31	Consecutive prime numbers; after 29 comes 31.
PS3	C) 112	Constant ratio ×2; 56×2=112.
PS4	C) 13	Fibonacci pattern: each term = sum of previous two (5+8=13).
PS5	B) 10	Differences −1,−2,−3,−4, next −5: 15−5=10.
PS6	B) U	Positions 1,5,9,13,17 (+4 each); next = 21 = U.
PS7	A) HT	First letter +2 (B,D,F,H); second letter −2 (Z,X,V,T).
PS8	C) 80	Constant ratio ×2; 40×2=80.
PS9	C) 218	Pattern is n³+2: 1+2,8+2,27+2,64+2,125+2,216+2=218.
PS10	B) 11	Odd positions: 8,9,10,? (+1 each) → 11; even positions: 12,13,14 (+1 each).
PS11	C) 42	Rule is n×(n+1): 4×5=20, so 6×7=42.
PS12	C) 121	81 is the square of 9; the square of 11 is 121.
PS13	C) 26	24 = sum of positions of C,A,T (3+1+20). Sum for D,O,G = 4+15+7 = 26.
PS14	B) Paper	A Painter creates art on a Canvas; a Writer creates text on Paper (surface used, not the tool).
PS15	C) Cactus	Rose, Lily, and Jasmine are commonly grouped as flowers; Cactus is classified as a succulent plant, not a flower type.
PS16	C) 30	Pattern is ×2 each time (2,4,8,16,32,64); 30 should be 32.
PS17	C) 63	Each term = sum of previous two terms: 15+24=39, 24+39=63.
PS18	B) N	Positions 26,23,20,17 (−3 each); next = 14 = N.
PS19	C) E25	Numbers are squares of position (1,4,9,16,25); letters are consecutive (A,B,C,D,E).
PS20	A) Cloth	Wood is the raw material used to make Furniture; Cotton is the raw material used to make Cloth.
PS21	D) 150	121, 144, and 169 are perfect squares (11², 12², 13²); 150 is not a perfect square.
PS22	C) 63	Rule is ×2, +1: 31×2+1 = 63.
PS23	A) Length	A Kilogram is a unit of Weight; a Metre is a unit of Length.
PS24	D) 64	Pattern is n²+2n: n=1..7 gives 3,8,15,24,35,48,63; 64 should be 63.
PS25	A) VWX	Each group of 3 consecutive letters jumps ahead by 3 positions to the next group of 3 consecutive letters.
PS26	B) Judge	A Thief's characteristic action is to Steal; a Judge's characteristic action is to Judge (deliver verdicts).
PS27	B) 9	4 is the square root of 16; the square root of 81 is 9.
PS28	B) V	Positions 10,13,16,19 (+3 each); next = 22 = V.
PS29	B) 33	Rule is ×2, −1: 17×2−1 = 33.
PS30	A) Web	A Bee lives in a Hive; a Spider lives in a Web.
PS31	D) 38	Pattern is n²+1 for n=2..7: 5,10,17,26,37,50. The term 38 is wrong; it should be 37.
PS32	B) B	Positions 16,19,23 — gaps of 3, then 4. Next position = 23+5 = 28, which wraps around (28−26=2) to the letter B.
PS33	B) Pen	A Locksmith's main working tool is a Key; an Author's main working tool is a Pen (Book is the product, not the tool).
PS34	B) 58	Differences: 1,4,9,16 (perfect squares 1²,2²,3²,4²). Next difference = 5²=25, so 33+25=58.
PS35	D) Tuesday	March, May, and August are months; Tuesday is a day of the week, not a month.

End of Book. Revise the Reference Chapter tables one final time before your exam, and re-attempt any MCQ you answered incorrectly on a fresh attempt at least once more.