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Question 289413: It takes 10 hours to fill a pool with the inlet pipe. It can be emptied in 15 hours with the outlet pipe. If the pool is half full to begin with, how long will it take to fill it from there if both pipes are open?
i think i have it at here but im not sure i worked it out to be..
1/10-1/15=1/2t
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! It takes 10 hours to fill a pool with the inlet pipe.
5 hrs to fill half the pool:
rate = 1/5 hrs/half-pool
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It can be emptied in 15 hours with the outlet pipe.
(15/2) hrs to empty half the pool
rate = (2/15) hrs/half-pool
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Working together let rate = x hrs/half-pool
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Equation:
1/5 - 2/15 = 1/x
3x - 2x = 15
x = 15 hrs (time to fill half of the pool)
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If the pool is half full to begin with, how long will it take to fill it from there if both pipes are open?
i think i have it at here but im not sure i worked it out to be..
1/10-1/15=1/2t
Using your equation:
Multiply thru by 30t to get:
3t-2t = 15
t = 15 hrs. (time to fill half of the pool)
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Cheers,
Stan H.
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