a family consists of two grandparents , two parents , and 3 grandchildren . the average age of the grandparents is 64 years , the average age of the parents is 39 years , and the average age of the grandchildren is 6 years . what is the average age ( in years ) of the family ? Pick:
A) 31
B) 32
C) 33
D) 34
E) 35

Rationale: total age of the grandparents = 64 ã — 2 = 128 total age of the parents = 39 ã — 2 = 78 total age of the grandchildren = 6 ã — 3 = 18 average age of the family = ( 128 + 78 + 18 ) / 7 = 224 / 7 = 32 years the answer is b .
Answer: B