Question

After $12$ years I shall be $3$ times as old as I was $4$ years ago. Find my present age?

Answer 1

Let my present age $=x$ years.
After $12$ years my age will be $x+12$ years.
$4$ years ago my age was $x-4$ years.
So $x+12=3(x-4)$
$\Rightarrow x+12=3x-12$
$\Rightarrow 3x-x=12+12$
$\Rightarrow 2x=24$
$\therefore x=12$ years
Therefore, the present age is $12$ years.