After 20 years, M

Let the Manoj’s present age be x yr.

Then, Manoj’s age after 20 yr = (x + 20) yr.

It is given that after 20 yr, Manoj’s age will be 5 times his present age.

Therefore, the equation is x + 20 = 5x

⇒ 20 = 5x – x

⇒ 20 = 4x

⇒ [Divide by 4 both sides]

⇒ 5 = x

Hence, the present age of Manoj is 5 yrs.