15 men take 21 days of 8 hours each to do a piece of work. How many days of 6 hours each would 21 women take, if 3 women do as much work as 2 men?
(a)18
(b)20
(c)25
(d)30
Answer
Answer (as printed): D
Explanation
3 women $\equiv$ 2 men. So, 21 women $\equiv$ 14 men. Less men, More days (Indirect Proportion). Less hours per day, More days (Indirect Proportion). Men $14:15$, Hours per day $6:8$ :: $21:x$. $\therefore (14 \times 6 \times x) = (15 \times 8 \times 21) \Leftrightarrow x = \frac{(15 \times 8 \times 21)}{(14 \times 6)} = 30$. $\therefore$ Required number of days = 30.
Explanation as extracted from the printed page; notation may be imperfect.