The average age of a father and a mother in a family is 36 years. The average age of the father, mother and their only daughter is 28 years. What is the age of the daughter?

Explanation

Average age of father and mother = 36 years Total age of father and mother = 36 × 2 = 72 years Average age of father, mother and daughter = 28 years Total age of father, mother and daughter = 28 × 3 = 84 years ∴ Age of daughter = 84 – 72 = 12 years