Multiple choice

The average age of 8 children of a family is 12 yr. if the age of 7 children are 12,8,14,11,9,13 and 15 yr, then the age of 8th child will be

  1. 12 yr

  2. 14 yr

  3. 13 yr

  4. 15 yr

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Total sum for 8 children = 8 * 12 = 96. Sum of 7 children = 12 + 8 + 14 + 11 + 9 + 13 + 15 = 82. Age of 8th child = 96 - 82 = 14.

AI explanation

Using the basic average formula, the total sum of the ages of all 8 children is 8 multiplied by 12, which equals 96 years. The sum of the ages of the 7 known children is 12 plus 8 plus 14 plus 11 plus 9 plus 13 plus 15, resulting in 82 years. The age of the 8th child is the difference between the total sum and the sum of the 7 children, so 96 minus 82 equals 14 years.