Question

Find Arjun's present age if twenty years from now, he will be thrice as old as he is today.

Answer 1

Let Arjun be $x$ years old now.

After 20 years, his age will be $x+20$ years.
According to question,
$x+20=3x.$
$\Rightarrow 3x-x=20$
$\Rightarrow 2x=20$
$\Rightarrow x=\frac{20}{2}=10$
Therefore, Arjun's present age is 10 years.