Question

A family consists of two grandparents, two parents and three grandchildren. The average age of the grandparents is $67$ years, that of the parents is $35$ years and that of the grandchildren is $6$ years. What is the average age of the family?

• A. $28\frac{4}{7}years$
• B. $31\frac{5}{7}years$
• C. $32\frac{1}{7}years$
• D. None of these

Answer 1

Answer: (B)

$31\frac{5}{7}years$

Required average $=\left(\frac{67\times 2+35\times 2+6\times 3}{2+2+3}\right)$
$=\left(\frac{134+70+18}{7}\right)$
$=\frac{222}{7}$
$=31\frac{5}{7}years$.