Question

Hari is twice as old as his son.Twenty years ago, he was four times as old as his son. Find their present age.

Answer 1

So to solve this problem

Let the age of his son$=x$

Age of Hari is $=2x$

Twenty years ago their ages are

Age of son $=x-20$

Age of Hari $=2x-20$

Relation between their ages $20$ years ago, Age of Hari$=4$(Age of his son )

$$\begin{gathered} 2x-20=4(x-20) \\ 2x-20=4x-80 \\ 80-20=4x-2x \\ 60=2x \\ \frac{60}{2}=x \\ 30=x \end{gathered}$$

So the present age of his son $=30$ years

So the present age of Hari

$$\begin{gathered} =2x \\ =2\left(30\right) \\ =60years \end{gathered}$$