1. Two pipes A and B can fill a tank in 20 minutes and 30 minutes respectively. If both pipes are opened together, the time taken to fill the tank is ?

50 minutes

12 minutes

25 minutes

15 minutes

Answer: 12 minutes


2. 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.

Answer: 14 min. 40 sec.


3. A cistern is normally filled in 8 hours but takes two hours longer to fill because of a leak in its bottom. If the cistern is full, the leak will empty it in ?

20 hrs

28 hrs

36 hrs

40 hrs

Answer: 20 hrs


4. A tap can empty a tank in one hour. A second tap can empty it in 30 minutes. If both the taps operate simultaneously, how much time is needed to empty the tank ?

20 minutes

30 minutes

40 minutes

45 minutes

Answer: 20 minutes


5. Three Taps 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 ?





Answer: 14


6. Two pipes can fill a cistern in 3 hours and 4 hours respectively and a waste pipe can empty it in 2 hours. If all the three pipes are kept open, then the cistern will be filled in ?

5 hours

8 hours

10 hours

12 hours

Answer: 12 hours


7. One pipe can fill a tank three times as fast as another pipe. If together the two pipes can fill the tank in 36 min, then the slower alone will be able to fill the tank in ?

81 min

108 min

144 min

192 min

Answer: 144 min


8. A tap can fill a cistern in 8 hours and another tap can empty it in 16 hours. If both the taps are open, the time (in hours) taken to fill the tank will be ?





Answer: 16


9. Two pipes can fill a cistern separately in 10 hours and 15 hours. They can together fill the cistern in ?

6 hours

7 hours

8 hours

9 hours

Answer: 6 hours


10. One fill pipe A is 3 times faster than second fill pipe B and takes 32 minutes less than the fill pipe B. When will the cistern be full if both pipes are opened together ?

6 min

8 min

12 min

10 min

Answer: 12 min