A certain number of men can finish a piece of work in 100 days. If there were 10 men less, it would take 10 days more for the work to be finished. How many men were there originally?
Answer: D
Originally let there be x men.
Less men, More days (Indirect Proportion)
Therefore, (x-10) : x :: 100 :110
=> (x - 10) * 110 = x * 100 => x= 110