Five men working six hours a day take eight days to fill a trench. How long does it take 3 men working eight hours a day to fill the same trench.

The correct answer is 10 days.

Step-by-step explanation:

To fill a trench, 5 men work for 6 hours a day for eight days.

Total work hours required is given by 5 * 6 * 8 = 240 hours.

The same work is supposed to be done by 3 men working 8 hours a day.

Let these three men need to work for x days.

Therefore total work hour these group of three men gave = 3 * 8 * x = 24x hours

Therefore the work hour of both the group of 5 men and 3 men should be equal.

⇒ 24x = 240

⇒ x = 10

Therefore the group of 3 men have to work for 10 days to fill the trench.