Pipes and Cistern - Important Formulas |Aptitude

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

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