Multiple choice

The sum of the ages of 10 boys is 100 and each of them differs by 4yrs from the average. Number of boys having age more than the average age is

  1. 0

  2. 10

  3. 5

  4. cannot be determined
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Average age = 100/10 = 10. If each differs by 4, the ages are 10-4=6 and 10+4=14. Let n be the number of boys with age 14. Then 14n + 6(10-n) = 100. 8n + 60 = 100, so 8n = 40, n = 5.

AI explanation

The average age of the boys is the sum of their ages divided by the number of boys, giving 100 / 10 = 10 years. Since the statement implies a symmetric distribution around this average, exactly half of the boys must be above the average to balance the half that is below it. Therefore, the number of boys with an age greater than the average age is 5.

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