Question 461969
Working alone Ann can clean the house in 7 hours.
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Ann's rate = 1/7 job/hr
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WOrking with Tom they can clean it in 4 hours.
Together rate = 1/4 job/hr
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How long will it take Tom to clean the house alone?
Tom's rate = 1/x job/hr
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Equation:
rate + rate = together rate
1/7 + 1/x = 1/4
4x + 28 = 7x
3x = 28 
x = 28/3 hrs = 9 1/3 hrs = 9 hrs 20 minutes (Tom's time to do job alone)
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Cheers,
Stan H.
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