After 12 years Manu will be 3 times as old as he was 4 years ago, Find his present age.

The correct answer is 12

Let Manus current age be x
∴ Manus age after 12 years = x + 12
Manus age 4 years ago = x - 4
∴ We can form the equation as follows
3 * (x - 4) = (x + 12)
∴ 3x - 12 = x + 12
or 3x - x = 12 + 12
∴ 2x = 24 or x = 12
∴ Manus presnt age is 12 years