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Question 104888: Bill takes 2hours and Monica takes 1hour to wash a car. How long will both take to do the same?
Answer by oberobic(2304)   (Show Source):
You can put this solution on YOUR website! Combined work efforts are similar to mixture problems. You need to figure out the "pure" rate of work per hour by each person.
In this case, Bill takes 2 hr to do 100% of the job, so he does 50% per hr.
In contrast, Monica does 100% of the job in 1 hr, so she does 100% per hr.
Working together they do the full job.
.5x +x = 1
1.5x = 1
x = 1/1.5 = 2/3 hr
ALWAYS check:
2/3*.5 = 1/3 = Bill's contribution
2/3*1 = 2/3 = Monica's contribution
1/3 +2/3 = 1 =full job.
Check.
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