SOLUTION: Filling a tank. A water tank has an inlet pipe and a drain pipe. A full tank can be emptied in 30 minutes if the drain is opened and an empty tank can be filled in 45 minutes wi

Algebra ->  Customizable Word Problem Solvers  -> Misc -> SOLUTION: Filling a tank. A water tank has an inlet pipe and a drain pipe. A full tank can be emptied in 30 minutes if the drain is opened and an empty tank can be filled in 45 minutes wi      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 191310This question is from textbook
: Filling a tank. A water tank has an inlet pipe and a drain
pipe. A full tank can be emptied in 30 minutes if the drain
is opened and an empty tank can be filled in 45 minutes
with the inlet pipe opened. If both pipes are accidentally
opened when the tank is full, then how long will it take to
empty the tank?
This question is from textbook

Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
the size of the tank is not a factor
so let's assume a size that's divisible by 30 and 45 ___ 90gal is good

the outlet passes 90gal in 30min or 3gal/min

the inlet passes 90gal in 45min or 2gal/min

with both open, the tank is losing 1gal/min (3-2)

emptying a 90gal tank at 1gal/min takes 90min