1. A can complete a piece of work in 16 days and B in 24 days. In what time they complete if they work together?
Ans: 9.6 days
2. A tap can fill a cistern in 8 minutes and another can fill it in 12 minutes. If both are opened simultaneously, find the time that the cistern will be full.
Ans: 4.8 min
3. If a pipe fills a tank in 15 minutes and a leak in the bottom empties it in 25 minutes, when both function simultaneously then in what time can the tank be filled?
Ans: 37.5 min.
4. A can reap a field in 8 days while A and B together can reap the same field in 6 days. In how many days will B alone can reap that field?
5. 32 men can do a piece of work in 18 days. In how many days can 36 men do that work?
Ans: 16 days
6. Two pipes A and B can fill a tank in 4 and 5 hours respectively. A drain pipe C can empty a full tank in 8 hours. In what time can the tank be filled when all the three are open simultaneously?
7. In a garrison, provision is sufficient for 600 soldiers for 15 days. But after 5 days 100 soldiers left the garrison. For how many days more the provision last for them?
Ans: 12 days
Total number of mandays = 15× 600 = 9000
Number of mandays completed = 5 × 600
Remaining mandays = 9000 − 3000 = 6000
Number of soldiers = 600 − 100 = 500
Number of days provision last =
= 12 days
8. Ravi can do a work in 20 days. He worked alone for 10 days and the remaining work was completed with the help of Hari in 2 days. In how many days will the total work be completed if they work together?
Ans: 4 days
9. A pipe can fill 80% of the cistern in 12 minutes. In how many minutes it can fill half of the cistern?
Ans: 7.5 minutes
10. A contractor employs 15 men to complete a work in 10 days. But after 8 days he notices that only 60% work has been finished. In order to finish the work in the stipulated time, how many more men are required?
11. A pipe fills a tank in 5 hours and a leak empties in 4 hours. When both function simultaneously, in what time can the tank be emptied?
Ans: 20 hours
12. 16 men can do a piece of work in 12 days. 5 days after they started the work, 4 more men joined them. How many days will they now take to complete the remaining work?
Ans: 5.6 days
Explanation: Total mandays required for the work = 12 × 16 = 192
Number of mandays completed in 5 days = 5 ×16 = 80
Remaining mandays = 192 − 80 = 112
Number of men available now = 16 + 4 = 20
Number of days required = = 5.6 days
13. A can build a wall in 18 days, B in 12 days and C in 15 days. In how many days will the wall be built if all the three work together?
14. A can do a piece of work in 40 days. He worked at it for 5 days after that B finished it in 21 days. In how many days can A and B together finish the work?
Ans: 15 days
15. 18 men can complete a piece of work in 33 days. How many more men are required to complete the same work in 27 days?
Explanation: Let the number of persons required to complete the work be 'x'
18 × 33 = x × 27
x = 22
22 − 18 = 4
4 more men are required
16. A drain pipe can empty of cistern in 21 minutes. In 9 minutes, what part of cistern can be emptied?
17. A contractor undertakes to do a piece of work in 30 days. He recruits 50 men at the beginning and 75 more after 20days and completes the work in stipulated time. If he had not engaged the additional men, in how many days the work would have been finished?
Explanation: Let the work take 'x' more days
50(30 + x) = 50 × 20 + 125 × 10 x = 15
work would have been finished in 30 + 15 = 45 days
18. Two pipes A and B can fill a cistern in 14 hours and 16 hours respectively. The pipes are opened simultaneously and it is found that due to leakage in the cistern it takes 32 minutes more time to be filled up. If the cistern is full, in what time would the leak empty it?
Ans: 112 Hours