Problema Solution

A girl is 21 years old and her brother is a third her age. When the girl is 36, what will be the age of her brother?

Answer provided by our tutors

The brother age is 21/3 = 7 year.

In 36 - 21 = 15 years the girl will be 36.

In 15 years her brother will be 15 + 7 = 22 years old.