Question

a contractor undertook to finish a piece of work in 100 days. He appointed 20 workers in the beginning but half of the work was finished in 60 days. How many workers should be added so that the work will be finished in the specified time?

Answer 1

Answer:

A contractor undertook to do a certain piece of work in 9 days. He employed a certain number of laborers. But, 6 of them being absent from the very first day, the rest could finish the work in 15 days . What is the number of men originally employed?

Let the number of men originally employed be n.

n*9 = (n-6)*15, or

9n = 15n - 90, or

15n - 9n = 6n = 90, or

n = 15.

So the contractor engaged 15 men, initially. to complete the work in 9 days.

So the work involved 15*9 = 135 man-days.

On the first day itself, 6 were absent that left only 9 men to do the work which they did in 15 days or involved 9*15 = 135 man-days. Correct.