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Question 130705: A can do a piece of work in 25 days and B can do a work in 20 days.both work together for 5days after that a leaves. how long will B need to finish the remaining work.
Answer by ptaylor(2198)   (Show Source):
You can put this solution on YOUR website! Let x= amount of time it will take B to finish the job
A works at the rate of 1/25 of the job per day
B works at the rate of 1/20 of the job per day
Together A & B work at the rate of 1/25 + 1/20=
4/100 + 5/100= 9/100 of the job per day
If they both work together for 5 days, they complete (9/100)*5 or
45/100 of the job, leaving 55/100 of the job yet to be done
B can do 1/20 of the job per day, so:
(1/20)*x=55/100 multiply each side by 100
5x=55 divide both sides by 5
x=11 days-----------------amount of time needed by B to finish the job
Hope this helps---ptaylor
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