A man’s age is three times his son’s age. Ten years ago he was five times his son’s age. Find their present ages.

Let a man’s son’s age be x years.

Therefore, a man’s age will be 3x years.

Ten years ago, their age was (x - 10) years and (3x - 10) years respectively.

According to the question,10 years ago,

A man’s age = 5 × A man’s son’s age 10 years ago

3x - 10 = 5(x - 10)

3x - 10 = 5x - 50

2x = 40

x = 20 and 3x = 60

Therefore, A man and his son's age are 60 and 20 years respectively.