<PRE><B>Question 445549</B>
Jake can complete a job in 5 hours while Jerry can complete the same job in 3 hours.
a) How long would it take to complete the job if both Jerry and Jake worked
together?
Jake rate = 1/5 job/hr
Jerry rate = 1/3 job/hr
Together rate = 1/x job/hr
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Equation:
rate + rate = together rate
1/5 + 1/3 = 1/x
3x + 5x = 15
8x = 15
x = 15/8 = 1 7/8 hrs = 1hr+(5/8)60 min = 1hr 52.5 minutes
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b) How long would it take to complete the job if Jake starts the job two hours before Jerry joins him?
---
Jake will complete 2(1/5) = 2/5 of the job.
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Solve:
(1/5)x + (1/3)x = 3/5 job
----
3x + 5x = 9
8x = 9
x = 9/8 hrs = 1 hr 7.5 minutes
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Cheers,
Stan H. 
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