Multiple choice

10 years ago, the average age of a family of five members was 38 years. Now, two new members join, whose age difference is 8 years. If the present average age of the family is the same as it was 10 years ago, what is the age (in years) of the new younger member? 10 साल पहले, पांच सदस्यों के एक परिवार की औसत आयु 38 वर्ष थी। अब, दो नए सदस्य जुड़ते हैं, जिनकी आयु का अंतर 8 वर्ष है। यदि परिवार की वर्तमान औसत आयु वही है जो 10 वर्ष पहले थी, तो नए युवा सदस्य की आयु (वर्षों में) क्या है?

  1. 15

  2. 9

  3. 10

  4. 17

  5. 12
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B Correct answer
Explanation

10 years ago, family of 5 had average age 38, so total age was 190. Now (10 years later), those 5 members are 10 years older each, so their total increased by 50 to 240. Let new members be x and x+8 years old. New family has 7 members with average 38, so total age = 7×38 = 266. Therefore 240 + x + (x+8) = 266, giving 2x + 248 = 266, so 2x = 18, x = 9 years. Option A (15) would require the younger member to be 15. Option C (10) doesn't satisfy the average.

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