Bunuel
The work done by a man is double the work done by a woman in the same time. If 10 men can do a piece of work in 8 days, then in how many days that work can be done by 3 men and 4 women?
(A) 4
(B) 80/11
(C) 8
(D) 16
(E) 18
Since a man can do double the work of a woman, one man is equivalent to two women. Thus, a group of 3 men and 4 women is equivalent to a group of 5 men. We are told that 10 men can do the work in 8 days and we need to find the number of days that 5 men can do the same work. Since the number of men is halved, the number of days will be doubled, which means that 5 men can do the work in 2 * 8 = 16 days.
Alternate Solution:The rate of 10 men is \(\frac{1}{8}\frac{\text{job}}{\text{day}}\), which means the rate of one man is \(\frac{1}{80}\frac{\text{job}}{\text{day}}\).
We are told that one man can do double the work of a woman, which means that the rate of one man is double the rate of one woman. Thus, the rate of one woman is \(\frac{1}{160}\frac{\text{job}}{\text{day}}\). Then, the rate of 3 men and 4 women is:
\(\Rightarrow 3\times\frac{1}{80} + 4\times\frac{1}{160}\)
\(\Rightarrow \frac{3}{80} + \frac{2}{80}\)
\(\Rightarrow \frac{5}{80}\)
\(\Rightarrow \frac{1}{16}\)
Thus, the rate of 3 men and 4 women is \(\frac{1}{16}\frac{\text{job}}{\text{day}}\). This means that 3 men and 4 women can do \(\frac{1}{16}\) of the job in one day, so it will take 16 days to complete the whole job.
Answer: D