Current age of father - 38 years

At the time of his boy's birth, father age - 19 years

If, current age of boy - 19 years

19 + 19 = Current age of father i.e 38 years.

Age of boy five years back = 19 - 5 ==> 14

So, son's age five years back will be == 14 Years

Ans :- 14 years