Question

5 men can dig 4 identical trenches in 7 hours. Assuming that all the men work at the same rate, how long will take 7 men to dig 9 such trenches?​

Answer 1

Answer:

7 trenches will take 7*7.5= 52.5 man hours. So if you have 5 men it will take them 52.5/5= 10.5 hours

Answer 2

Step-by-step explanation:

If 3 men build 2 trenches in 5 hours, that means that 3 men build 1 trench in 2.5 hours. That means that 1 man builds 1/3 of a trench in 2.5 hours, or 1 man builds 1 trench in 7.5 hours. If it takes 7.5 man hours to build a trench, then it will take 7 times that to build 7 trenches, or 7*7.5=52.5 man hours. 52.5 man hours of work can be completed by 5 men in 52.5/5 = 10.5 hours. So, the answer is 10.5 hours