Pipes and Cisterns Problems with Solutions

1. 
   

   Two pipes can fill a tank in 10 hrs and 15 hrs, respectively. However, leakage at the bottom of the tank delays the filling of the tank by 3 hrs when both the pipes are open simultaneously. How much time would the leak take to empty the full cistern?

1. A. 22 hrs     
2. B. 18 hrs        Correct Answer
3. C. 12 hrs      
4. D. 21 hrs      

2.  

   
   

   A cistern can be filled by two pipes filling separately in 12 and 16 mins, respectively. Both pipes are opened together for a certain time but being clogged, only seven -eighths of full quantity water flows through the former and only five- sixths through the latter pipe. The obstructions, however, being suddenly removed, the cistern is filled in 3 mins from that moment. How long was it before the full flow began?

1. A. 4.5 mins       Correct Answer
2. B. 2.5 mins      
3. C. 3.5 mins      
4. D. 5.5 mins      

3.  

   
   

   A tank can be filled by a tap in 20 mins and by another tap in 60 min. Both the taps are kept open for 10 min and then the first tap is shut of. After this, the tank will be completely filled in

1. A. 10 min     
2. B. 12 min      
3. C. 15 min      
4. D. 20 min        Correct Answer

4.  

   
   

   Pipe A can fill an empty tank in 30 hrs while B can fill it in 45 hrs. Pipes A and B are opened and closed alternatively i.e., first pipe A is opened, then B, again A and then B and so on for 1 hr each time without any time lapse. In how many hrs the tank will be filled when it was empty, initially?

1. A. 36       Correct Answer
2. B. 54      
3. C. 48      
4. D. 60      

5.  

   
   

   A vessel is fully filled with a special liquid. Four litres of liquid is drawn out of this vessel and is replaced with water. If the ratio of the special liquid to the water becomes 1:2, then what is the capacity of the vessel?

1. A. 8 litres     
2. B. 10 litres      
3. C. 12 litres        Correct Answer
4. D. 14 litres      

6.  

   
   

   A tap can fill a tank in 48 mins, whereas another tap can empty it in 2 hrs. If both the taps are opened at 11:40 a.m., then the tank will be filled at

1. A. 12:40 p.m.     
2. B. 1:30 p.m.      
3. C. 1:00 p.m.        Correct Answer
4. D. 1:20 p.m.      

7.  

   
   

   When the waste pipe is closed, two taps can separately fill a cistern in 10 and 12 mins respectively. When the waste pipe is opened they together fill it in 15 mins. How long does it take the waste pipe to empty the cistern, when the taps are closed?

1. A. 7 mins 10 s     
2. B. 8 mins 34 s        Correct Answer
3. C. 12 mins      
4. D. 10 mins      

8.  

   
   

   Two pipes A and B can fill a tank in 20 and 30 hrs, respectively. Both the pipes are opened to fill the tank but when the tank is one-third full, a leak develops in the tank through which one-fourth water supplied by both pipes goes out. What is the total time taken to fill the tank?

1. A. 14 2/3 hrs       Correct Answer
2. B. 15 hrs      
3. C. 12 1/2 hrs      
4. D. 9 1/2 hrs      

9.  

   
   

   A cistern has 3 pipes A, B and C. A and B running alone can fill it up in 2 hrs and 3 hrs respectively, while C is a waste pipe. If all the 3 pipes be opened at once, 7.24 of the cistern will be filled up in 30 mins. In what time can C empty the full cistern?

1. A. 5 hrs     
2. B. 4 hrs        Correct Answer
3. C. 3 hrs      
4. D. 6 hrs      

10.  

    
    

    A cistern has a leak which would empty it in 8 hrs. A tap is turned on which admits 6 litres a minute into the cistern and it is now emptied in 12 hrs. The cistern can hold

1. A. 7860 litres     
2. B. 6840 litres      
3. C. 8640 litres        Correct Answer
4. D. None of these      

11.  

    
    

    A bath can be filled by the cold water pipe in 10 mins and by hot water pipe in 15 mins (independently each). A person leaves the bathroom after turning on both pipes simultaneously and returns at the moment when the bath should be full. Finding, however, that the waste pipe has been opened he now closes it. In 4 mins more, bath is full. In what time would be the waste pipe empty it?

1. A. 6 mins     
2. B. 9 mins      
3. C. 3 mins      
4. D. 15 mins        Correct Answer