Question

the ratio of the present ages of a son and his father is 1 : 5 and that of his mother and father is 4 : 5. after 2 years the ratio of the age of the son to that of his mother becomes 3 : 10. what is the present age of the father?

Answer 1

let the present age of son ,mother and fater be
1x,4x and 5x respectively
after two years age of son will be x+2
and age of mother be 4x+2
x+2/4x+2=3/10
cross multiply we get
10x+20=12x+6
2x=12
x=6
age of father=5x
=5*6=30