SOLUTION: A water tank can be filled by an inlet pipe in 8 hours. It takes 3 times as long for the outlet pipe to empty the tank. How long will it take to fill the tank if both pipes are ope

Algebra ->  Rate-of-work-word-problems -> SOLUTION: A water tank can be filled by an inlet pipe in 8 hours. It takes 3 times as long for the outlet pipe to empty the tank. How long will it take to fill the tank if both pipes are ope      Log On


   

Question 804522: A water tank can be filled by an inlet pipe in 8 hours. It takes 3 times as long for the outlet pipe to empty the tank. How long will it take to fill the tank if both pipes are open?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Rate of filling:
( 1 tank ) / ( 8 hrs )
Rate of emptying:
( minus 1 tank ) / ( 24 hrs )
Let the combined rate =
( 1 tank filled ) / ( t hrs )
------------------------
+1%2F8+-+1%2F24+=+1%2Ft+
Multiply both sides by +24t+
+3t+-+t+=+24+
+2t+=+24+
+t+=+12+
It will take 12 hrs to fill the tank
with both pipes open