A family consists of grandparents, parents and three grand children. 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? Choices:
A) 28 4⁄7 years  B) 31 5⁄7 years  C) 32 1⁄7 years  D) 27 1⁄2 years  E) None of these
Required average = (67×2+35×2+6×3/2+2+3)   = (134+70+18/7)=222/7   = 31 5⁄7 years   Answer 31 5⁄7 years
<result>B</result>
A family consists of grandparents, parents and three grand children. 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?