Question 233416
A bathtub can be filled by the cold water faucet in 12 minutes and by the hot water faucet in 13 minutes. How long does it take to fill the tub if both faucets are open?
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Cold water rate: 1/12 tub/min
Hot water rate: 1/13 tub/min
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together rate = 1/x tub/min
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Equation:
rate + rate = together rate
1/12 + 1/13 = 1/x
(12+13)/(12*13) = 1/x
x = (12*13)/(12+13)
x = 6.24 minutes (time required to fill if both faucets are open)
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Cheers,
Stan H.