Question

The sum of ages of a father and his son is 55
years. Find the sum of their ages after 15 years​

Answer 1

$let \: the \: age \: of \: father \: be \: x \\ then \: age \: of \: sun \: be \: 55 - x \\ \: \: \: \: \: according \: to \: question \\ after \: 15 \: years \\ age \: of \: father \: = x + 15 \\ age \: of \: sun \: = 40 - x$