30 men can do a piece of work in 16 days. How many men would be required to do the same work in 20 days?
(a)12
(b)24
(c)36
(d)48
(e)None of these
Answer
Answer (as printed): B
Explanation
Let the required number of men be $x$. More days, Less men (Indirect Proportion) $$\begin{aligned} & \therefore 20: 16:: 30: x \Leftrightarrow 20 x=16 \times 30 \\ & \Leftrightarrow x=\left(\frac{16 \times 30}{20}\right)=24 . \end{aligned}$$
Explanation as extracted from the printed page; notation may be imperfect.