Pipes and Cistern


  1. There are two pumps to fill a tank with water. First pump can fill the empty tank in 8 hours, while the second in 10 hours. If both the pumps are opened at the same time and kept open for 4 hours, the part of tank that will be filled up is:









  1. View Hint View Answer Discuss in Forum

    As per the given in question , we have

    Part of the tank filled in an hour by both pumps =
    1
    +
    1
    =
    5 + 4
    =
    9
    8104040

    Correct Option: A

    As per the given in question , we have

    Part of the tank filled in an hour by both pumps =
    1
    +
    1
    =
    5 + 4
    =
    9
    8104040

    ∴ Part of the tank filled in 4 hours =
    4 × 9
    =
    9
    4010


  1. If 3/5 th of a cistern is filled in 1 minute, the time needed to fill the rest is









  1. View Hint View Answer Discuss in Forum

    According to question ,

    Time taken to fill the
    3
    of the cistern = 60 seconds
    5

    ∴ Time taken in filling
    2
    part =
    60 × 5
    ×
    2
    535

    Correct Option: A

    According to question ,

    Time taken to fill the
    3
    of the cistern = 60 seconds
    5

    ∴ Time taken in filling
    2
    part =
    60 × 5
    ×
    2
    = 40 second
    535



  1. Pipes P and Q can fill a tank in 10 and 12 hours respectively and C can empty it in 6 hours. If all the three are opened at 7 a.m., at what time will one-fourth of the tank be filled ?









  1. View Hint View Answer Discuss in Forum

    From the given question ,
    When all three pipes are opened , then

    Part of tank filled in 1 hour =
    1
    +
    1
    -
    1
    10126

    Part of tank filled in 1 hour =
    6 + 5 - 10
    =
    1
    6060

    ∴ The tank will be filled in 60 hours.

    Correct Option: B

    From the given question ,
    When all three pipes are opened , then

    Part of tank filled in 1 hour =
    1
    +
    1
    -
    1
    10126

    Part of tank filled in 1 hour =
    6 + 5 - 10
    =
    1
    6060

    ∴ The tank will be filled in 60 hours.
    ∴ One fourth of the tank will be filled in 15 hours =
    1
    × 60i.e the tank will be filled at 10 p.m.
    4


  1. A tap can fill an empty tank in 12 hours and another tap can empty half the tank in 10 hours. It both the taps are opened simultaneously, how long would it take for the empty tank to be filled to half its capacity ?









  1. View Hint View Answer Discuss in Forum

    As per the given in question , we have

    Part of the tank filled by pipe A in 1 hour =
    1
    12

    Part of the tank emptied by pipe B in 1 hour =
    1
    20

    Correct Option: A

    As per the given in question , we have

    Part of the tank filled by pipe A in 1 hour =
    1
    12

    Part of the tank emptied by pipe B in 1 hour =
    1
    20

    Part of the tank filled in 1 hour =
    1
    -
    1
    =
    5 - 3
    =
    1
    12206030

    ∴ Tank will be filled in 30 hours.



  1. 3/4 part of a tank is full of water.. When 30 litres of water is taken out, the tank becomes empty. The capacity of the tank is









  1. View Hint View Answer Discuss in Forum

    Let the capacity of the tank be q litres.
    According to the question,

    3q
    = 30
    4

    ⇒ 3q = 30 × 4

    Correct Option: C

    Let the capacity of the tank be q litres.
    According to the question,

    3q
    = 30
    4

    ⇒ 3q = 30 × 4
    ⇒ q =
    30 × 4
    = 40 litres
    3