The sum of the ages of a father and son is 45 years. Five years ago, the product of their ages was four times the fathers age at that time. The present age of father and son  Choose the correct option:
A) 34,11 B) 35,10 C) 36,9 D) 40,5 E) 41,5
Explanation:   Let sons age = x years. Then fathers age = (45 - x)years.   (x—5)(45—x—5) = 4(45- x - 5) hence (x—5) = 4 so x = 9   Their ages are 36 years and 9 years.   Answer: Option 36,9
<result>C</result>
The sum of the ages of a father and son is 45 years. Five years ago, the product of their ages was four times the fathers age at that time. The present age of father and son