Published: 05 Aug 2019

The problems of pipes and cisterns usually have two kinds of pipes, Inlet pipe and Outlet pipe / Leak.

**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 a cistern or a reservoir, emptying it, is known as an outlet.

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

Part filled in 1 hour = 1/x

For example, if a pipe takes 6 hours to fill a tank completely, say of 12 liters, then in 1 hour, it will fill 1 / 6 th of the tank, i.e., 2 liters.

* 2.* If a pipes can empty a full tank in y hours, then :

Part emptied in 1 hour = 1/y.

For example, if a pipe takes 6 hours to empty a tank completely, say of 18 liters, then in 1 hour, it will empty 1 / 6 th of the tank, i.e., 3 liters.

** 3.** If a pipe can fill a tank in xx hours and another pipe can fill it in yy hours, then both the pipes together can fill the tank in xy / x+y hours.

** 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, the net part filled in 1 hour = (1/x - 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, the net part emptied

In 1 hour = (1/y - 1/x).

** 6.** If we have a number of pipes such that some fill the tank and some empty it, and we open all of them together, then in one hour, part of the tank filled/emptied = ∑ (1 / m

https://gyangossip.com/quantitative-aptitude/mock-test/T4434

https://gyangossip.com/quantitative-aptitude/mock-test/T10136