The sum of ages of a man and his son is 45 years. Five years ago, the product of their ages is equal to the four times of his father’s age at that time. Find the age of father and son.

36, 09

let the age of father is x and age of son is y . 

ATQ, 

 x + y = 45 years 

 ( x - 5 ) ×  ( y - 5 ) = 4  ( x - 5 )

  ( y - 5 ) = 4

    y = 9 years 

now , 

x + 9 = 45 

x  = 36 years