A family consists of a grandfather, grandmother, father, mother, 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?
1
\(28\frac{4}{7}\;years\)
2
\(31\frac{5}{7}\;years\)
3
\(32\frac{1}{7}\;year\)
4
None of these