Question 210948
It usually takes Eva 3 hours longer to do the monthly payroll than it takes Cindy. They start working on it together at 9.00 AM and at 5.00 PM they have 90% of it done. If Eva took s 2 hour lunch break while Cindy had none, then how much longer will it take for them to finish the payroll working together?
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Cindy's rate is 1/x  job/hr
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Eva's rate is 1/(x+3) job/hr
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From 9am to 5pm they have worked 8 hrs
In that time they have accomplished
8*Cindy's rate + 6*Eva's rate = 90% of the job
8(1/x)+6*[1/(x+3)] = 0.90 job
I get x = 24.7
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Solve that for "x"; then you will know Cindy
and Eva's rates which are 1/x = 1/24.7 and 1/27.7).
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To get the time remaining for them to finish
the job.
k(1/24.7 + 1/27.7) = 0.10 of the job
k(0.0766) = 0.10
k = 1.306 hrs.

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Cheers,
Stan H.