Arithmatical - Pipes Cisterns

Important facts and formulae
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 = 1 / x.

3.

I. If a pipe can empty a tank in y hours, then :

part emptied in 1 hour = 1 / y.

II. 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 = (1 / x - 1 / y).

III. 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 emptied in 1 hour = (1 / y - 1 / x).