**Q1. Two pipes A and B can fill a tank in 15 hours and 20 hours respectively while a third pipe C can empty the full tank in 25 hours. All the three pipes are opened in the beginning. After 10 hours C is closed. Find, in how much time will the tank be full?**

(a) 12 hrs

(b) 8 hrs

(c) 10 hrs

(d) 14 hrs

**Q2. Three pipes A, B and C can fill a tank in 6 minutes, 8 minutes and 12 minutes respectively. The pipe C is closed 6 minutes before the tank is filled. In what time will the tank be full?**

(a) 6 min

(b) 4 min

(c) 5 min

(d) Data inadequate

**Q3. A pipe can empty a tank in 12 minutes and another pipe can empty it in 16 minutes. If both the pipes are opened simultaneously, find the time in which a full tank is emptied.**

(a) 6 minutes

(b) 6 (1/7) minutes

(c) 6 (2/7) minutes

(d) None of these

**Q4. Two pipes A and B can fill a cistern in 12 minutes and 15 minutes respectively. There is also an outlet C. If all the three pipes are opened together, the tank is full in 10 minutes. How much time will be taken by C to empty the full tank?**

(a) 10 min

(b) 20 min

(c) 15 min

(d) Data inadequate

**Q5. A cistern can be filled by two pipes in 30 and 40 minutes respectively. Both the pipes were opened at once, but after some time the first was shut up, and the cistern was filled in 10 minutes more. How long after the pipes had been opened was the first pipe shut up?**

(a) 90/11 minutes

(b) 90/7 minutes

(c) 90/13 minutes

(d) 45/2 minutes

**Q6. Two pipes A and B can fill a tank in 36 minutes and 48 minutes respectively. If both the pipes are opened simultaneously, after how much time should B be closed so that the tank is full in 27 minutes?**

(a) 10 min

(b) 12 min

(c) 14 min

(d) 16 min

**Q7. A pipe can fill a tank in 10 minutes and another pipe in 15 minutes, but a third pipe can empty it in 5 minutes. The first two pipes are kept open for 4 minutes in the beginning and then the third pipe is also opened. In what time is the cistern emptied?**

(a) 25 minutes

(b) 20 minutes

(c) 24 minutes

(d) 28 minutes

**Q8. Three pipes A, B and C are connected to a tank. A and B together can fill the tank in 60 minutes, B and C together in 40 minutes and C and A together in 30 minutes. In how much time will each pipe fill the tank separately?**

(a) 80 min, 240 min, 48 min

(b) 40 min, 120 min, 24 min

(c) 60 min, 250 min, 64 min

(d) None of these

**Q9. One filling pipe A is 3 times faster than second filling pipe B. If B can fill a cistern in 16 hours, then find the time when the cistern will be full if both fill pipes are opened together.**

(a) 5 hrs

(b) 6 hrs

(c) 4 hrs

(d) Data inadequate

**Q10. 8 taps are fitted to a water tank. Some of them are water taps to fill the tank and the remaining are outlet taps used to empty the tank. Each water tap can fill the tank in 12 hours and each outlet tap an empty it in 36 hours. On opening all the taps, the tank is filled in 3 hours. Find the number of water taps.**

(a) 5

(b) 4

(c) 3

(d) 2