Pipes and Cistern important notes - Aptitude Questions and Answers

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.
If a pipe can fill a tank in x hours, then:
part filled in 1 hour = 1 .
x
If a pipe can empty a tank in y hours, then:
part emptied in 1 hour = 1 .
y
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 - 1 .
x y
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 = 1 - 1 .
y x

part filled in 1 hour =	1	.
	x

part emptied in 1 hour =	1	.
	y

the net part filled in 1 hour =		1	-	1		.
		x		y

the net part emptied in 1 hour =		1	-	1		.
		y		x