Question

John's present age to Andrew's present age is 3:1. In 6 years time, the ratio of John's age to Andrew's age will be 5:2. What is John's present age?

Answer 1

Call x the present age of John, and y, age of Andrew
We have 2 equations

(1) x = 3y

(2) `(x + 6) = (5/2)(y + 6) -> 2(3y + 6) = 5(y + 6)` ->

Present age of Andrew: `y = 30 - 12 = 18`

Present age of John: `x = 3y = 54`