Multiple choice

The average age of 37 boys in a class is 12 years. If the age of their teacher is also included, the average increases by 1.5 year. The teacher's age in years is / एक कक्षा में 37 लड़कों की औसत आयु 12 वर्ष है। यदि उनके शिक्षक की उम्र भी शामिल है, तो औसत 1.5 वर्ष बढ़ जाता है। वर्षों में शिक्षक की आयु है

  1. 60

  2. 79

  3. 69

  4. 54
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Total age of 37 boys = 37 × 12 = 444 years. When teacher is included, average becomes 12 + 1.5 = 13.5 years for 38 people, so total = 38 × 13.5 = 513 years. Teacher's age = 513 - 444 = 69 years. Option A (60) would be if you incorrectly used 37 × 1.5 instead of 38 × 13.5.

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