Question 620087: One pipe can fill a tank in 36 minutes, a second can fill it in 9 minutes, and a third can fill it in 12 minutes. If the tank is empty, how long will the three pipes, operating together, take to fill it?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! One pipe can fill a tank in 36 minutes, a second can fill it in 9 minutes, and a third can fill it in 12 minutes. If the tank is empty, how long will the three pipes, operating together, take to fill it?
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The rates are 1/36 ; 1/9 ; 1/12
Together rate is 1/x
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Equation:
(1/36) + (1/9) + (1/12) = 1/x
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Multiply thru by 36x to get:
x + 4x + 3x = 36
8x = 36
x = 4.5 minutes (time to do the job together)
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Cheers,
Stan H.
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