SOLUTION: Two people together can do a certain job in twenty minutes. If one of them can do the job alone in forty-five minutes, how long will the other person take to do the job alone?
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Question 121716: Two people together can do a certain job in twenty minutes. If one of them can do the job alone in forty-five minutes, how long will the other person take to do the job alone? Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! Two people together can do a certain job in twenty minutes. If one of them can do the job alone in forty-five minutes, how long will the other person take to do the job alone?
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Together DATA:
Time = 20 min/job ; Rate = 1/20 job/min
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One person DATA:
Time = 45 min/job ; Rate = 1/45 job/min
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2nd person DATA:
Time = x min/job ; RAte = 1/x job/min
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EQUATION:
rate + rate = together rate
1/45 + 1/x = 1/20
Multiply thru by 180x to get:
4x + 180 = 9x
5x = 180
x = 36 min (time for the 2nd person to do the job alone)
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Cheers,
Stan H.
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