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?
Let m = number of men
Let w = work
Let d = days
We know that m * d = w
Since we are given that m men can finish a piece of work in 100 days, we have
m*100=w
Thus, 100m = w. (1)
We are also given that if there were 10 men less (m-10) it will take 10+100=110 days to finish it.
So we have (m-10)(110)=w,
110m-1100=w. (2)
Now, (1) = (2) because they both have w and so they’re equal.
Thus we have 110m-1100=100m
Subtracting both sides by 100m we have 10m - 1100 = 0.
Adding both sides by 1100 we have 10m = 1100
Dividing both sides by 10 we have m = 110.
Therefore there were 110 men originally.