A contractor undertakes to do a piece of work in 40 days. He engages 100 men at the beginning and 100 more after 35 days and completes the work in stipulated time. If he had not engaged the additional men, how many days behind schedule would it be finished?
Answer: A
Let the work done by 1 man in 1 day be 1 unit. Total work = Work done in first 35 days + Work done in last 5 days = \(100 \times 35 + (100+100) \times 5 = 3500 + 200 \times 5 = 3500 + 1000 = 4500\) units. If the additional men were not engaged, the 100 men would have to do the entire work. Time taken = Total work / Number of men = 4500 / 100 = 45 days. The work would be finished 5 days behind the scheduled 40 days.