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Question
A can do a piece of work in 20 days and B in 15 days. They worked together on it for 6 days and then A left. How long will B take to finish the remaining work?
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Solution
Given,
A can do a piece of work in = 20 days
B can do a piece of work in = 15 days
∴ A's 1-day work =`1/20`
B's 1-day work = `1/15`
(A+B)'s 1-day work =`1/20+1/15`
`=(3+4)/60=7/60`
(A+B)'s 6 days work =`7/60xx6=7/10`
Remaining work =`1-7/10`
`=(10-7)/10=3/10`
B can do 1 work in = 15 days
B can do `3/10` work in =`15xx3/10` days
`=45/10`days =`9/2` days = `4 1/2` days
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