Question

Five years hence, father's age will be $3$ times the age of his son. Five years ago, father was seven times as old as his son. The age of the son at present is

• A. $10$ years
• B. $15$ years
• C. $20$ years
• D. $40$ years

Answer 1

Answer: (A)

$10$ years

Let $5$ years ago, the ages of son and father were $x$ and $7x$ years respectively, then
$3(x+5+5)=7x+5+5$
$\Rightarrow 3x+30=7x+10$
$\Rightarrow 4x=20$
$\Rightarrow x=5$
Thus, present age of son $=x+5=10$ years