Question

After 5 years a man's age will be three times his son's age and 5 years ago he was seven times as old as his son . find their present ages

Answer 1

Let present age of father be x and son be y
After 5 years, father's age = 5+x
After 5 years, son's age = 5+y
By the question
(5+x) = 3(5+y) (i)
(x-5) = 7(y-5) (ii)
Solve (i) and (ii)
we get 
father's present age = 40 years
and son's present age = 10 years