A person says that his son is 5 times as old as his daughter and his wife is 5 times older than his son and he is twice the age of his wife . The sum total of all the ages equals the age of the grand mother who celebrated her 81st birthday today. How old was his son?

Correct Answer: 50 yrs

Let the daughter age be 'x'Therefore, Son age = 5x, Mother age = 25x, Person age = 50x.

Thus we get, x+5x+25x+50x = 8181x = 81x = 1

Daughter's age = 1, Son's = 5, Mother's = 25, Person's age = 50.