Question

18 years ago,a mother was 3 times as old as her son.now the mother is only twice as old as her son.then the sum of their present ages:

Answer 1

let mother's age be x and son's age be y.
18 yrs ago:
(x-18)=3(y-18)...eqn 1

Now:
x=2y....eqn 2

solve 1 and 2 to get their ages'.