SOLUTION: One can fill a tank in 4 hours. Together with a second pipe, the tank can be filled in 3 hours. How long would it take the second pipe alone to fill the tank?

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Question 353826: One can fill a tank in 4 hours. Together with a second pipe, the tank can be filled in 3 hours. How long would it take the second pipe alone to fill the tank?
Found 2 solutions by nerdybill, stanbon:
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
One can fill a tank in 4 hours. Together with a second pipe, the tank can be filled in 3 hours. How long would it take the second pipe alone to fill the tank?
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Let x = time (hours) for second pipe to fill alone
then
3(1/4 + 1/x) = 1
multiplying both sides by 4x:
3(x + 4) = 4x
3x + 12 = 4x
12 hours = x

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
One can fill a tank in 4 hours. Together with a second pipe, the tank can be filled in 3 hours. How long would it take the second pipe alone to fill the tank?
---
1st pipe rate = 1/4 job/hr
---
Together rate = 1/3 job/hr
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2nd pipe rate = 1/x job/hr
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Equation:
rate + rate = together rate
1/4 + 1/x = 1/3
Multiply thru by 12x to get:
3x + 12 = 4x
x = 12 hrs (time required for the 2nd pipe to do the job alone)
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Cheers,
Stan H.