The present age of a Manoj is twice the sum of the ages of his two children. After 20 years, the age of Manoj will become equal to the sum of the ages of his two children. What is the present age of Manoj?

40 years

ATQ,

Let sum of Manoj's two children = x

Given, present age of Manoj = 2x

After 20 years Manoj's age will be 2x +20

After 20 years sum of children's age will be x + 40

Given, 2x + 20 = x + 40

          x = 20

Manoj's present age = 40 years