In a family, a couple has a son and a daughter. The age of the father is three times that of his daughter and the age of the son is half of that of his mother. The wife is 9 years younger to her husband and the brother is seven years older than his sister. What is the age of the mother ?

Explanation:-

Let the daughter's age be x years.
Then, father's age = (3x) years.
Mother's age = (3x - 9) years; Son's age = (x + 7) years.
So, x + 7 = (3x-9)/2 ⇔ 2x + 14 = 3x - 9 ⇔ x = 23.
Therefore Mother's age = (3X - 9) = (69 - 9) years = 60 years.