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| Question 611352:  A 400-gallon water storage tank is filled by a single inlet pipe, and two identical outlet pipes can be used to supply water to the surrounding fields (see the figure). It takes 4 hours to fill an empty tank when both outlet pipes are open. When one outlet pipe is closed, it takes 3 hours to fill the tank. Find the flow rates (in gallons per hours) in and out of the pipes.
 Inlet?
 Outlet?
 Answer by stanbon(75887)
      (Show Source): 
You can put this solution on YOUR website! A 400-gallon water storage tank is filled by a single inlet pipe, and two identical outlet pipes can be used to supply water to the surrounding fields (see the figure). It takes 4 hours to fill an empty tank when both outlet pipes are open. When one outlet pipe is closed, it takes 3 hours to fill the tank. Find the flow rates (in gallons per hours) in and out of the pipes. Inlet?
 Outlet?
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 Let i by the rate of the inlet pipe.
 Let t be the rate of one of the outlet pipes.
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 Equation:
 i - 2t = 1/4
 i - t = 1/3
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 Subtract and solve for "t":
 t = (1/3-(1/4)
 t = 1/12 job/hr (flow rate of each of the outlet pipes)
 Each outlet pipe removes 400/12 = 33 1/3 gallons per hour
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 Solve for "i":
 i - t = 1/3
 i  = 1/12 + 1/3
 i = 15/36 = 5/12 job/hr (flow rate of the input pipe)
 The input pipe feeds (5/12)400 = 166 2/3 gallons per hour.
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 Cheers,
 Stan H.
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