# Aptitude  Pipes  Practice Q&A

1. A cistern can be filled by a tap in 3 hours while it can be emptied by another tap in 8 hours. If both the taps are opened simultaneously, then after how much time will the cistern get filled?

 4.8 hr 2.4 hr 3.6 hr 1.8 hr

2. Three pipes A, B and C can fill a tank in 6 hours. After working at it together for 2 hours, C is closed and A and B can fill the remaining part in 7 hours. The number of hours taken by C alone to fill the tank is:

 10 12 14 16

3. Two pipes can fill a tank in 20 and 24 minutes respectively and a waste pipe can empty 3 gallons per minute. All the three pipes working together can fill the tank in 15 minutes. The capacity of the tank is:

 60 gallons 100 gallons 120 gallons 180 gallons

4. Two pipes A and B can fill a tank in 15 minutes and 20 minutes respectively. Both the pipes are opened together but after 4 minutes, pipe A is turned off. What is the total time required to fill the tank?

 10 min. 20 sec. 11 min. 45 sec. 12 min. 30 sec. 14 min. 40 sec.

5. A pump can fill a tank with water in 2 hours. Because of a leak, it took 2$\dfrac{1}{3}$ hours to fill the tank. The leak can drain all the water of the tank in:

 4$\dfrac{1}{3}$hours 7 hours 8 hours 14 hours

6. Three taps A, B and C can fill a tank in 12, 15 and 20 hours respectively. If A is open all the time and B and C are open for one hour each alternately, the tank will be full in:

 6 hours 6$\dfrac{2}{3}$hours 7 hours 7$\dfrac{1}{2}$hours

7. Pipe A can fill a tank in 8 hours, pipe B in 4 hours and pipe C in 24 hours. If all the pipes are open, in how many hours will the tank be filled?

 2.4 hr 3 hr 4 hr 4.2 hr

8. Pipes A and B can fill a tank in 8 and 24 hours respectively. Pipe C can empty it in 12 hours. If all the three pipes are opened together, then the tank will be filled in:

 18 hr 6 hr 24 hr 12 hr

9. Three pipes A, B and C can fill a tank from empty to full in 30 minutes, 20 minutes, and 10 minutes respectively. When the tank is empty, all the three pipes are opened. A, B and C discharge chemical solutions P,Q and R respectively. What is the proportion of the solution R in the liquid in the tank after 3 minutes?

 $\dfrac{5}{11}$ $\dfrac{6}{11}$ $\dfrac{7}{11}$ $\dfrac{8}{11}$

10. Two pipes A and B can fill a tank in 2 and 6 minutes respectively. If both the pipes are used together, then how long will it take to fill the tank?

 3 min 2.5 min 2 min 1.5 min