SSC GD Constable previous year question
The average of thirteen numbers is 57. The average of first three numbers is 48, and that of the next seven numbers is 58. The 11th number is two times the 12th number and 12th number is 3 less than the 13th number. What is the average of the 11th and 13th numbers?
Asked in SSC GD Constable 2025: 07 Feb 2025 Shift 1 · Quantitative Aptitude
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Correct answer: (B) 72
Total of 13 numbers = 13×57=741. First 3 sum=144, next 7 sum=406, so sum of last 3 (11th,12th,13th) = 741−144−406=191. Let 12th=x, 11th=2x, 13th=x+3; sum: 2x+x+x+3=191 → 4x=188 → x=47. So 11th=94, 13th=50, average=(94+50)/2=72.
हिंदी में प्रश्न
तेरह संख्याओं का औसत 57 है। पहली तीन संख्याओं का औसत 48 है, और अगली सात संख्याओं का औसत 58 है। 11वीं संख्या 12वीं संख्या की दोगुनी है और 12वीं संख्या 13वीं संख्या से 3 कम है। 11वीं और 13वीं संख्याओं का औसत क्या है?
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सही उत्तर: (B) 72
13 संख्याओं का योग = 13×57=741। पहली 3 का योग=144, अगली 7 का योग=406, अतः अंतिम 3 (11वीं,12वीं,13वीं) का योग = 741−144−406=191। मान लें 12वीं=x, 11वीं=2x, 13वीं=x+3; योग: 4x+3=191 → x=47। अतः 11वीं=94, 13वीं=50, औसत=(94+50)/2=72।
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