IB ACIO Grade II practice question
The difference between the value of a number increased by 25% and the value of the same number decreased by 10% is 280. What is the number?
From a IB ACIO Grade II Quantitative Aptitude practice set · Quantitative Aptitude
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Correct answer: (C) 800
Let the number be x. (100 + 25)% of x − (100 − 10)% of x = (25 + 10)% of x = 35% of x = 280. So x = 280 × 100/35 = 800. (Subtracting the percentages, 25% − 10%, is the wrong move — the two changes are on opposite sides of x, so they add.)
हिंदी में प्रश्न
एक संख्या को 25% बढ़ाने पर प्राप्त मान और उसी संख्या को 10% घटाने पर प्राप्त मान का अंतर 280 है। वह संख्या क्या है?
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सही उत्तर: (C) 800
माना संख्या x है। x का (100 + 25)% − x का (100 − 10)% = x का (25 + 10)% = x का 35% = 280। अतः x = 280 × 100/35 = 800। (प्रतिशतों को घटाना, 25% − 10%, गलत है — दोनों परिवर्तन x के विपरीत ओर हैं, इसलिए वे जुड़ते हैं।)
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