Question

At present ,the sum of the ages of a father and a son is 60 . what willbe the sum of their ages after 15 years ?

Answer 1

Let the age of father and son be a and b respectively.

According to the question,

The sum of the ages of father and son = 60

•°• a + b = 60   ------  ①

After 15 years,

Age of father = a + 15

Age of son    =  b + 15

Sum of their ages after 15 years = (a + 15) + (b + 15)

(a + 15) + (b + 15)

a + 15 + b + 15

= a + b + 30

= 60 + 30  ( from ① )

= 90

The sum of their ages after 15 years will be $90$.