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 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 ? Correct Answer 31( 5\/7)

Required average = (67 * 2 + 35 * 2 + 6 * 3) / (2 + 2 + 3)

                           = (134 + 70 + 18) / 7  =  222 / 7 = 31(5/7) years.

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