Note- Problems on Pipes and Cisterns are same as that of Time and Work.
Important Concepts
If a pipe fills a tank in x hours, then the part filled in 1 hour = \frac { 1 }{ x }
If a pipe empty a tank in x hours, then the part of tank emptied in 1 hour = \frac { 1 }{ x } hours
If a Pipe A alone fills a tank in x hours and another Pipe B alone fills in y hours.
Then the time taken to fill the tank when both pipes are open = \frac { xy }{ x+y } hours.
If two pipes A and B together fills a tank in x hours and A alone fills in y hours
Then the time is taken by B to fill the tank = \frac { xy }{ y-x } hours
If a Pipe A alone empties a tank in x hours and another Pipe B alone empty it in y hours.
Then the time taken to empty the tank when both pipes are open = \frac { xy }{ x+y } hours
If A, B, and C alone fills a tank in x, y, and z hours, then the time is taken to fill the tank when all are open= \frac { xyz }{ (xy+yz+zx) } hours
If a pipe can fill a tank in x hours and another pipe can empty the full tank in y hours (x>y), then the net part emptied in 1 hour will be= \frac { 1 }{ y } -\frac { 1 }{ x }
Example-
Two pipes can fill a tank in 24 hours and 36 hours respectively. If both the pipes are opened at the same time, then how much time will be taken to fill the tank?
Solution-
Pipe A in 1 hour = 1/24
Pipe B in 1 hour = 1/36
Pipe A and B together in 1 hour = (1/24) + (1/ 36) = 1/9
So, Both Pipes will take 9 hours to fill the tank. (Reason- Check Statement 1)