hi there! :) i have a question about APPLICATIONS OF LINEAR EQUATION :
One pipe can fill a tank in 45 minutes and another pipe can fill it in 30 minutes. If this two pipes are open and a third pipe is bringing water from the tank, it takes 27 minutes to fill the tank. How long will it take the third pipe alone to empty a full tank.

Question

amistre64 · Answer

you have no information given to determine this with.  In order for the 3rd pipe to empty the tank, it needs to have a rate of change defined for it.  Also, its unclear as to what the situation is ....

anonymous · Answer

sorry :) I've just corrected the question :) just read it again please.. 
thank you :*

amistre64 · Answer

(total input rate) - (output rate) = 27 minutes

(total input rate) - (27minutes) = (output rate)

amistre64 · Answer

both inlets, in a one minute time span, can fill 1/45 and 1/30 of the tank

what is 1/45 + 1/30 ?