1. A can do a piece of work in 6 days and B can do the same work in 12 days. How long will they take to complete it, if they both work together?

2. Anil and Sunil work together and finish a work in 8 days. Anil alone can do it in 12 days. How many days will Sunil take to finish the work alone?

3. Raju can do a piece of work in 3 hours. Navin can do it in 6 hours. How long will they take if they both work together?

4. A can do a work in 15 days. B in 25 days and C in 30 days. How long will they take to do the work if they work together?

5. One tap fills a tub in 15 minutes and another tap in 12 minutes. How long does it take to fill the tub, if both the taps are open simultaneously?

6. One tap can fill a tank in 60 minutes while the other can empty it in 50 minutes. If the tank is full and both the taps are opened, in what time will the tank be emptied?

7. Sandeep and Sekhar together can do a piece of work in 15 hours. If Sandeep alone can do it in 20 hours, how long will Sekhar alone take to do the work?

8. A cistern can be filled by a tap in 6 hours. After four hours how much part of the cistern will remain empty?

9. Two taps can fill a cistern in 6 and 7 minutes respectively. If the taps are opened turn by turn each for a minute, find the time taken by them to fill the cistern?

10. A and B can do 1/3 rd of a work in a day. A alone can do the whole work in 12 days. How long will B take alone to finish the work?

11. A and B can do a piece of work in 10 hours. B and C in 15 hours, while C and A can do it in 12 hours. How long with Raju take to complete the work independently?

12. If 8 men can mow a field in 12 days, in how many days would 6 men mow another field which is 4 times as big?

13. A garrison of 200 men has provision sufficient for 24 weeks. At the end of the first week a reinforcement of 80 men arrives. How long did the food last them?

14. A contractor undertook to build a road in 100 days. He employed 110 men. After 45 days, he found that only ¼ could be built. In order to complete the work in time how many more men should be employed?