<PRE><B>Question 191435</B>
A plumber can install a dishwasher in 50 minutes. If the plumber brings his apprentice to help, the job takes 40 minutes. How long would it take the apprentice working alone to install the dishwasher?
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Plumber DATA:
time = 50 minutes/job ; rate = 1/50 job/min
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Together DATA:
time = 40 minutes/job ; rate = 1/40 job/min
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Apprentice DATA:
time = x min/job ; rate = 1/x job/min
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Equation:
rate + rate = together rate
1/50 + 1/x = 1/40
Multiply thru by 200x to get:
4x + 200 = 5x
x = 200 minutes (time the apprentice would need to do the job alone)
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Cheers,
Stan H.</PRE>