If A : B : C = 2 : 3 : 5 and A = x% of (B + C), then x is equal to -

Answer: Option C

Let A = 2k, B = 3k, C = 5k
A = x% of (B + C)
⇒ 2k = x% of (3k + 5k) = x% of 8k
$$\begin{array}{rl}& \Rightarrow \frac{x}{100}=\frac{\text{2k}}{\text{8k}}=\frac{1}{4}\\ & \Rightarrow x=\frac{100}{4}=25\end{array}$$