Question

Two taps A and B can together fill a swimming pool in 15 days. The taps A and B are kept open for 12 days and then the tap B is closed. It took another 8 days for tap A to fill the pool. How many days does each tap require to fill the pool?

Answer 1

wo taps A and B together fill a swimming pool i 15 days . Tap A and B are kept open for 12 days and then tap B is closed . It takes another 8 days for the swimming pool to be filled. How many days each tap require to fill the swimming pool
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Let A and B be the rates of the 2 taps.
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Equation:
15A + 15B = 1 job
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20A + 12B = 1 job
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Multiply thru the top equation by 12
multiply thru the bottom equation by 15
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180A + 180B = 12
300A + 180B = 15
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Subtract and solve for A
120A = 3
A = 1/40 job/day (A's rate)
A would take 40 days to fill the pool alone.
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Solve for "B"
20A + 12B = 1
1/2 + 12B = 1
12B = 1/2
B = 1/24 job/day (B's rate)
B would take 24 days to fill the pool alone.