Question

Five years ago a man was seven times as old as his son. Five years hence, The father will be three times as old as his son. Find their present ages.

Answer 1

Let Five years ago the age of son be $x$ years and age of father be $7x$ years

Present age of son $=x+5$

Present age of father $=7x+5$

5 years later their age will $(x+10)$ and $(7x+10)$

$\therefore 7x+10=3(x+10)$

$7x-3x=20$

$4x=20$

$x=5$

So, the present age of son$=x+5=5+5=10years$

and the present age of father$=7x+5=35+5=40years$