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

Answer: Option B

Solution(By Examveda Team)

Required average
$$\eqalign{ & {\text{ = }} {\frac{{67 \times 2 + 35 \times 2 + 6 \times 3}}{{2 + 2 + 3}}} \cr & {\text{ = }} {\frac{{134 + 70 + 18}}{7}} \cr & = \frac{{222}}{7} \cr & = 31\frac{5}{7}{\text{ years}} \cr} $$