### A family consists of grandparents, 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. $28 \frac{4}{7} \text { years }$

B. $31 \frac{5}{7} \text { years }$

C. $32 \frac{1}{7} \text { years }$

D. None of these

$\begin{array}{l}\text{ Required average }\\ =\Large\frac{67\times2+35\times2+6\times3}{2+2+3}\\ =\Large\frac{134+70+18}{7}\\ =\Large\frac{222}{7}\\ =31\Large\frac{5}{7}\small\text{ years }\end{array}$