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Arithmetic Aptitude :: Pipes and Cistern

  1. Inlet:

    A pipe connected with a tank or a cistern or a reservoir, that fills it, is known as an inlet.

    Outlet:

    A pipe connected with a tank or cistern or reservoir, emptying it, is known as an outlet.

  2. If a pipe can fill a tank in x hours, then:

    part filled in 1 hour  = \(\frac { 1 } { X}\)   .
     
  3. If a pipe can empty a tank in y hours, then:

    part emptied in 1 hour =\(\frac { 1 } { Y}\)    .
     
  4. If a pipe can fill a tank in x hours and another pipe can empty the full tank in y hours (where y > x), then on opening both the pipes, then   

    the net part filled in 1 hour = \(\frac { 1 } { X}-​​\)\(\frac { 1 } { Y}\)                      
               
  5. If a pipe can fill a tank in x hours and another pipe can empty the full tank in y hours (where x > y), then on opening both the pipes, then

    the net part emptied in 1 hour =. [ \(\frac { 1 } { Y}\)  - \(\frac { 1 } { X}\)  ]         .