Question 698744
Solution:
Let, son's age be 'x'.

So, Father's present age is 5x.

Now, by the question, after 15 years, fathers, age=5x+13 and son's age =x+13 and,

father's age will exceeds twice that of his son by 8 , 
Hence we get:

5x + 13 = 2( x + 13) + 8 
5x + 13 = 2x + 26 + 8 
5x - 2x = 26 - 13 + 8
3x = 13 + 8
3x = 21 
x = 7 years,

hence the present son's age is 7 years , 
and father age is 5(x) = 5* 7 
= 35 years, 

when the son was born the father's age would be : 
35 - 7 = 28 years. 

Thanks , 
Best regards,