Aptitude Questions: Pipes & Cistern Set 10

Hello Aspirants. Welcome to Online Quantitative Aptitude Section with explanation in AffairsCloud.com. Here we are creating question sample in Pipes & Cistern which is common for all competitive exams. We have included Some questions that are repeatedly asked in bank exams !!!

1. If a pipe A can fill a tank 3 times faster than pipe B and takes 32 minutes less than pipe B to fill the tank. If both the pipes are opened simultaneously, then find the time taken to fill the tank?
   A. 14 minutes
   B. 12 minutes
   C. 15 minutes
   D. 16 minutes
   E. None of the Above
   
   Answer & Explanation

   Answer – B. 12 minutes
   Explanation :
   3x – x = 32
   x = 16
   1/16 + 1/48 = 4/48
   Time taken to fill the tank = 48/4 = 12 minutes
   
   
2. Two pipes P and Q can fill a tank in 24 minutes and 27 minutes respectively. If both the pipes are opened simultaneously, after how much time should B be closed so that the tank is full in 8 minutes?
   A. 14 minutes
   B. 12 minutes
   C. 15 minutes
   D. 18 minutes
   E. None of the Above
   
   Answer & Explanation

   Answer – D. 18 minutes
   Explanation :
   Required time = y(1-(t/x)) = 27(1-(8/24))= 18 minutes
   
   
3. A full tank gets emptied in 8 minutes due to the presence of a leak in it. On opening a tap which can fill the tank at the rate of 9 L/min, the tank get emptied in 12 min. Find the capacity of a tank?
   A. 120 L
   B. 240 L
   C. 216 L
   D. 224 L
   E. None of the Above
   
   Answer & Explanation

   Answer – C. 216 L
   Explanation :
   a = 8; b = 9; C = 12
   Capacity of a tank = a*b*c/c-a = 8*9*12/4 = 216 Litre.
   
   
4. If a pipe A can fill a tank 3 times faster than pipe B. If both the pipes can fill the tank in 42 minutes, then the slower pipe alone will be able to fill the tank in?
   A. 148 minutes
   B. 124 minutes
   C. 154 minutes
   D. 168 minutes
   E. None of the Above
   
   Answer & Explanation

   Answer – D. 168 minutes
   Explanation :
   Time is taken by pipe A = x
   Time is taken by pipe B = x/3
   1/x + 3/x = 1/42
   x = 168 minutes
   
   
   
5. A large cistern can be filled by two pipes P and Q in 15 minutes and 10 minutes respectively. How many minutes will it take to fill the Cistern from an empty state if Q is used for half the time and P and Q fill it together for the other half?
   A. 6.5 minutes
   B. 7.5 minutes
   C. 8.5 minutes
   D. 9.5 minutes
   E. None of the Above
   
   Answer & Explanation

   Answer – B. 7.5 minutes
   Explanation :
   Part filled by P and Q = 1/15 + 1/10 = 1/6
   Part filled by Q = 1/10
   x/2(1/6 + 1/10) = 2/15 = 15/2 = 7.5 minutes
   
   
6. A pipe can fill a cistern in 8 hours. After half the tank is filled, three more similar taps are opened. What is the total time taken to fill the cistern completely?
   A. 3 hours
   B. 2 hours
   C. 5 hours
   D. 4 hours
   E. None of the Above
   
   Answer & Explanation

   Answer – C. 5 hours
   Explanation :
   In One hour pipe can fill = 1/8
   Time is taken to fill half of the tank = 1/2 * 8 = 4 hours
   Part filled by four pipes in one hour = (4*1/8) = 1/2
   Required Remaining Part = 1/2
   Total time = 4 + 1 = 5
   
   
7. Two pipes P and Q are opened together to fill a tank. Both the pipes fill the tank in time “x” If Q separately took 16 minutes more time than “x” to fill the tank and Q took 36 minutes more time than “x” to fill the tank, then find out the value of x?
   A. 48 minutes
   B. 24 minutes
   C. 54 minutes
   D. 68 minutes
   E. None of the Above
   
   Answer & Explanation

   Answer – B. 24 minutes
   Explanation :
   Time is taken to fill the tank by both Pipes x = √a*b
   x = √16*36 = 4 * 6 = 24
   
   
8. A Cistern has an inlet pipe and outlet pipe. The inlet pipe fills the cistern completely in 1 hour 20 minutes when the outlet pipe is plugged. The outlet pipe empties the tank completely in 6 hours when the inlet pipe is plugged. If there is a leakage also which is capable of draining out the water from the tank at half of the rate of the outlet pipe, then what is the time taken to fill the empty tank when both the pipes are opened?
   A. 3 hours
   B. 2 hours
   C. 5 hours
   D. 4 hours
   E. None of the Above
   
   Answer & Explanation

   Answer – B. 2 hours
   Explanation :
   Inlet pipe Efficiency = 100/(8/6) = 75%
   Outlet pipe Efficiency = 100/(6) = 16.66%
   Efficiency of leakage = half of the rate of the outlet pipe = 8.33%
   Net Efficiency = 75 – (16.66 + 8.33) = 50%
   Required time = 100/50 = 2 hours
   
   
9. A Cistern has an inlet pipe and outlet pipe. The inlet pipe fills the cistern completely in 1 hour 20 minutes when the outlet pipe is plugged. The outlet pipe empties the tank completely in 4 hours when the inlet pipe is plugged. If both pipes are opened simultaneously at a time when the tank was one-third filled, when will the tank fill thereafter?
   A. 3 hours
   B. 2 hours
   C. 5 hours
   D. 4 hours
   E. None of the Above
   
   Answer & Explanation

   Answer – B. 2 hours
   Explanation :
   Inlet pipe Efficiency = 100/(8/6) = 75%
   Outlet pipe Efficiency = 100/(4) = 25%
   Net Efficiency = 75 – 25 = 50%(1/3)filled
   2/3 filled = 100%
   Required time = 100/50 = 2 hours
   
   
10. Two pipes P and Q can fill a cistern in 10 hours and 20 hours respectively. If they are opened simultaneously. Sometimes later, tap Q was closed, then it takes total 8 hours to fill up the whole tank. After how many hours Q was closed?
    A. 4 hours
    B. 5 hours
    C. 2 hours
    D. 6 hours
    E. None of the Above
    
    Answer & Explanation

    Answer – A. 4 hours
    Explanation :
    Pipe P Efficiency = 100/10 = 10%
    Pipe Q Efficiency = 100/20 = 5%
    Net Efficiency = 15%
    15x + 10(8-x) = 100
    x = 4