SOLUTION: Jeremy and his dad can wash his car together in 40 minutes. Jeremy can wash it by himself in 70 minutes. How long would it take his dad to wash it by himself?
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Question 751335: Jeremy and his dad can wash his car together in 40 minutes. Jeremy can wash it by himself in 70 minutes. How long would it take his dad to wash it by himself? Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! Jeremy and his dad can wash his car together in 40 minutes. Jeremy can wash it by himself in 70 minutes. How long would it take his dad to wash it by himself?
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together rate: 1/40 job/min
Jeremy rate::: 1/70 job/min
Dad rate::::: 1/x job/min
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Equation:
rate + rate = together rate
1/70 + 1/x = 1/40
40x + 70*40 = 70x
30x = 70*40
x = 93 1/3 minutes (Time for dad to do the job alone)
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Cheers,
Stan H.
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