Question

Harsha is $40$ years old and Ritu is $60$ years old. How many years ago was the ratio of their ages $3:5$?

• A. $10$ years
• B. $20$ years
• C. $37$ years
• D. $5$ years

Answer 1

The correct option is A $10$ years

Let $x$ years ago, the ratio of their ages be $3:5$.
Then, $\frac{40-x}{60-x}=\frac{3}{5}\Rightarrow 200-5x=180-3x$
$\Rightarrow 2x=20\Rightarrow x=10$ years.