The difference of two numbers is 20% of the larger number. If the smaller number is 12, the larger one is :

Answer: Option A

Let the number be x
Then,
$$\begin{array}{rl}& \iff x-12=20\%\text{ of }x\\ & \iff x-\frac{x}{5}=12\\ & \iff \frac{4x}{5}=12\\ & \iff x=\frac{12\times 5}{4}\\ & \iff x=15\end{array}$$