Question

A father is three times as old as his son. After twelve years, his age will be twice as that of his son then. Find their present ages.

Answer 1

Let’s assume the present ages of the father as x years and that of his son’s age as y years. 

From the question it’s given that, 

Father is 3 times as old as his son. (Present) 

So, the equation formed is 

x = 3y 

⇒ x – 3y = 0……. (i) 

Also again from the question it’s given as, 

After 12 years, father’s age will be (x + 12) years and son’s age will be (y + 12) years. 

Furthermore, the relation between their ages after 12 years is given below 

x + 12 = 2(y + 12) 

⇒ x + 12 = 2y + 24 

⇒ x – 2y – 12 = 0…… (ii) 

Solving (i) and (ii), we get the solution 

By using cross-multiplication, we have 

x = 36, y = 12 

Hence, the present age of father is 36 years and the present age of son is 12 years.