SOLUTION: It takes 8 hours to fill a pool with the inlet pipe. It can be emptied in 12 hours with the outlet pipe. If the pool is 1/2 full to begin with, how long will it take to fill it fro

Algebra ->  Rate-of-work-word-problems -> SOLUTION: It takes 8 hours to fill a pool with the inlet pipe. It can be emptied in 12 hours with the outlet pipe. If the pool is 1/2 full to begin with, how long will it take to fill it fro      Log On


   



Question 669609: It takes 8 hours to fill a pool with the inlet pipe. It can be emptied in 12 hours with the outlet pipe. If the pool is 1/2 full to begin with, how long will it take to fill it from there if both pipes are open?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
It takes 8 hours to fill a pool with the inlet pipe.
It can be emptied in 12 hours with the outlet pipe.
If the pool is 1/2 full to begin with, how long will it take to fill it from there if both pipes are open?
:
let t = time when both valves are left open
:
let the completed job = 1 (full pool)
:
t%2F8 - t%2F12 = 1%2F2
multiply by 24, resulting in
3t - 2t = 12
t = 12 hrs to complete filling the pool