Question

John’s age in 5 years time will be the same as Jack’s age is now. In two years, Jack will be twice as old as John. How old are they now?

Answer 1

Let's say John's age is x and Jack's age is y

(1) x + 5 = y
(2) y + 2 = 2(x + 2)

Now if we substitute equation (1) into equation (2) we get:

x + 5 + 2 = 2(x + 2)
x + 7 = 2x + 4
x = 3

If x = 3, then from equation (1) we get:
3 + 5 = y
y = 8

Therefor John is 3 years old and Jack is 8 years old