A father said to his son, "I was as old as you are at present at the time of your birth." If the father's age is 38 years now. Five years ago the age of son was :

Let us assume the present age of child is P years.
Then according to question,
I was as old as you are at present at the time of your birth.
Father's age were at the time of son's birth = P years
Again According to question
Present age of father = 38
Father's age were at the time of son's birth + Present age of Son = 38
P + P = 38
2P = 38
? P = 19 years
Hence, 5 years ago the age of son was 19 - 5 = 14 years