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?

Answer 1

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`