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Question
A can do a work in 15 days and B in 20 days. If they together work on it for 4 days; what fraction of the work will be left?
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Solution
A's 1-day work = `1/15`
B's 1-day work = `1/20`
(A+B)'s 1-day work =`1/15+1/20`
`=(4+3)/60=7/60`
(A+B)'s 4 days work =`7/60xx4=7/15`
Remaining work =`1-7/15=(15-7)/15`
`=8/15`
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