A certain number of men can finish a piece of work in 10 days. However, if there were 10 less men it will take 10 days more for the work to be finished. How many men were there originally?  Choose the correct choice:
A) 10 men
B) 30 men
C) 40 men
D) 20 men
E) none of these
Let x be the number of men originally   Thus, 10x=(10+10)(x-10)   10x=20(x-10)   x=2(x-10)   x = 20   ANSWER:20 men
<result>D</result>
A certain number of men can finish a piece of work in 10 days. However, if there were 10 less men it will take 10 days more for the work to be finished. How many men were there originally?