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Question 806900: You have 4 valves, the first valve took 1 hour to fill a pool, the 2nd valve took 2 hours to fill a pool, the 3rd valve took 3 hours to fill a pool and the fourth valve took 4 hours to fill a pool, if you opened all four valves at the same time, how long would it take to fill the pool?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! You have 4 valves, the first valve took 1 hour to fill a pool, the 2nd valve took 2 hours to fill a pool, the 3rd valve took 3 hours to fill a pool and the fourth valve took 4 hours to fill a pool, if you opened all four valves at the same time, how long would it take to fill the pool?
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The valve rates are 1,1/2,1/3,1/4 job/hr
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Together rate = 1/x
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Equation:
1 + 1/2 + 1/3 + 1/4 = 1/x
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Multiply thru by 12x to get:
12x + 6x + 4x + 3x = 12
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25x = 12
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x = 12/25
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Time = 12/25 hr = 0.48 hr = 0.48*60 = 28.8 minutes = 28min 28seconds
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Cheers,
Stan H.
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