Aman’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 Aman’s son’s age be x years. Therefore, Aman’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, Aman’s age = 5 × Aman’s son’s age 10 years ago

3x − 10 = 5(x − 10)

3x − 10 = 5x − 50

Transposing 3x to R.H.S and 50 to L.H.S, we obtain

50 − 10 = 5x − 3x

40 = 2x

Dividing both sides by 2, we obtain

20 = x

Aman’s son’s age = x years = 20 years

Aman’s age = 3x years = (3 × 20) years = 60 years