Question

The sum of ages of a man and his son is 45 years. Five years ago, the product of their ages was four times the man's age at the time. Find their present ages.

Answer 1

Let the present age of the man be

Then present age of his son is

Five years ago, man’s age

And his son’s age

Then according to question,

So, either

Or

But, the father’s age never be 5 years

Therefore, when then

Hence, man’s present age isand his son’s age is