SOLUTION: When the drain is opened on a swimming pool it takes the pool 6 hours to drain. When a small pump is used, it is able to drain in 5 hours. How many small pumps must be used to dr

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Question 995830: When the drain is opened on a swimming pool it takes the pool 6 hours to drain. When a small pump is used, it is able to drain in 5 hours. How many small pumps must be used to drain the pool in 2 hours?
What I have so far,
Let x = number of small pumps
(1/6) + x(1/5) = 1/2
But I get x = 5/3
So, am I to conclude that I need 2 pumps and they will drain the pool in under 2 hours?
Found 2 solutions by stanbon, ikleyn:
Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website!
When the drain is opened on a swimming pool it takes the pool 6 hours to drain. When a small pump is used, it is able to drain in 5 hours. How many small pumps must be used to drain the pool in 2 hours?
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Small pump DATA:
rate = 1/5 job/hr
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Equation:
time * work rate per unit * # of units = work done
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2(1/5)x = 1 job
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(2/5)x = 1
x = (5/2) # of small pumps needed
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If you include the work done by the drain without the pumps you get:
2((1/6)+(1/5)x) = 1 job
[(1/3)]+(2/5)x] = 1
(2/5)X = 2/3
(X/5) = 1/3
x = 5/3 small pumps
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Cheers,
Stan H.
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Answer by ikleyn(52802) (Show Source):
You can put this solution on YOUR website!
.
When the drain is opened on a swimming pool it takes the pool 6 hours to drain. When a small pump is used, it is able to drain in 5 hours. How many small pumps must be used to drain the pool in 2 hours?
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Two and half pumps :-).

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