Question

The sum of the present ages of father and his son is 65 years. Ten years ago the ratio of their ages was 7:2. What will be the ratio of their ages ten years hence?

Answer 1

let the present age of father and son be x and respectively
so according to question

$x + y = 65 \\ \frac{x - 10}{y- 10} = \frac{7}{2}$

2x-20=7y-70
x=(7y-50)/2

put value of x in eq.1 (x+y=65) and get your answer.

Answer 2

let the present age of father and son be x and respectively

so according to question

\begin{gathered}x + y = 65 \\ \frac{x - 10}{y- 10} = \frac{7}{2} \end{gathered}

x+y=65

y−10

x−10

=

2

7

2x-20=7y-70

x=(7y-50)/2

put value of x in eq.1 (x+y=65) and get your answer.