Question

ten years ago the age of a father was four times of his son. ten years hence the age of the father will be twice that of his son the present ages of father and son are

Answer 1

x+10=2x
2x=x+10
2x-x=10
x=10 years
y=2x
y=2*10
 =20 years
x is the age of son and y is the age of father

Answer 2

F-10=4(S-10) on solving this one gets F-4S=-30....1
F=10=2(S+10) on solving this one gets F-2S=10....2
solve both the equation and you get F=50 S=20