SOLUTION: A tank can be filled by a hose in 15 hours. It can be emptied by a drainpipe in 25 hours. If the drainpipe is open while the tank is being filled, how long does it take to fill the

Algebra ->  Rate-of-work-word-problems -> SOLUTION: A tank can be filled by a hose in 15 hours. It can be emptied by a drainpipe in 25 hours. If the drainpipe is open while the tank is being filled, how long does it take to fill the      Log On


   



Question 513152: A tank can be filled by a hose in 15 hours. It can be emptied by a drainpipe in 25 hours. If the drainpipe is open while the tank is being filled, how long does it take to fill the tank?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
A tank can be filled by a hose in 15 hours. It can be emptied by a drainpipe in 25 hours. If the drainpipe is open while the tank is being filled, how long does it take to fill the tank?
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Fill rate: 1/15 job/hr
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Drain rate: 1/25 job/hr
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Together rate: 1/x job/hr
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Equation:
rate - rate = rate
1/15 - 1/25 = 1/x
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Multiply thru by 75x to get:
5x - 3x = 75
2x = 75
x = 37.5 hrs (time to fill the tank together)
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Cheers,
stan H.
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