Question

the age of the father is twice the sum of the ages of his two children after 20 years his age will be equal to the sum of the ages of his children find the age of the father​

Answer 1

Let the age of father be x and the sum of ages of two children be y year.

x = 2y (Equation 1)

By the second condition

x + 20 = y + 40

[Note that the both children will add 20 year in their ages]

x - y = 20 (Equation 2)

From Equation (1) and (2)

2y - y = 20

y = 20 and x = 40

Age of father = 40 years