Question

A father is three times as old as his son .5 years ago father's age was four times his son's age . Find their present age

Answer 1

Let the present age of son be x.
Then father age be 3x.

5 years ago,

son age=x-5
father age=3x-5

A/q; 4(x-5)=3x -5
4x-20=3x-5
4x-3x=-5+20
x=15

So,son age=15
father age=45

Answer 2

let the present age of father be x yrs and son be y yrs
x=3y
and from 2nd case
x-5=4(y-5)
x-4y=-15
-y=-15
y=15
x=45