SOLUTION: Pipes A,B,C are connected to a swimming pool. Pipe A fills an empty pool in forty-five minutes and Pipe C empties a full pool in thirty minutes.Pipe B fills the pool. If all three

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Question 841581: Pipes A,B,C are connected to a swimming pool. Pipe A fills an empty pool in forty-five minutes and Pipe C empties a full pool in thirty minutes.Pipe B fills the pool. If all three pipes are left open then it takes them thirty minutes to fill an empty pool. How long would it take Pipe B alone to fill an empty pool ?
Found 3 solutions by richwmiller, ewatrrr, josmiceli:
Answer by richwmiller(17219)   (Show Source):
You can put this solution on YOUR website!
1/45+1/b-1/30=1/30
1/45+1/b=2/30
1/45+1/b=3/45
1/b=2/45
b=45/2= 22.5 minutes to fill the pool alone

Answer by ewatrrr(24785)   (Show Source):
You can put this solution on YOUR website!

Hi,
1/45 + 1/x - 1/30 = 1/30 ||Multiplying thru by 90x so as all denominators = 1
2x + 90 - 3x = 3x
90 = 4x
x = 22.5min , time it takes for Pipe C to fill the Pool

Answer by josmiceli(19441)   (Show Source):
You can put this solution on YOUR website!
Pipe A's rate of filling is pools/minute
Pipe C's rate of emptying is pools/minute ( minus for emptying )
Let B's rate of filling = pools/minute
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I can add the rates of the 3 pipes

Multiply both sides by

Pipe B alone can fill the pool is 22.5 minutes
check answer:

OK