There are 340 vacancies for a particular post in an organisation. Experience shows that 15\% of the candidates interviewed get rejected. How many candidates should be interviewed to fill all the vacancies?
(a)226
(b)391
(c)400
(d)420
(e)None of these
Answer
Answer (as printed): C
Explanation
Let the total number of candidates be $x$. Then, $(100-15) \%$ of $x=340 \Rightarrow 85 \%$ of $x=340$ $$\begin{aligned} & \Rightarrow \frac{85}{100} x=340 \\ & \Rightarrow x=\left(\frac{340 \times 100}{85}\right)=400 . \end{aligned}$$
Explanation as extracted from the printed page; notation may be imperfect.