<PRE><B>Question 318958</B>
 A water tank has an inlet pipe and a drain pipe. 
A full tank can be emptied in 30 minutes if the drain is opened and an empty tank can be filled in 45 minutes with the inlet pipe opened.
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Drain pipe DATA:
time = (1/2) hr/job ; rate = 2 job/hr
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Inlet pipe DATA:
time = (3/4) hr/job ; rate = (4/3) job/hr
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If both pipes are accidentally opened when the tank is full, then how long will it take to empty the tank?
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Together DATA:
time = x hr/job ; rate = 1/x job/hr
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Equation:
drain rate - fill rate = together rate
2 - (4/3) = 1/x
2/3 = 1/x
x = 3/2 hrs to drain the tank
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Cheers,
Stan H.


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