Question

A can do a piece of work in 30 days . he works at it for 5 days and then b finish it in 20 days in what time a and b togehter do it

Answer 1

a will do his work In one day =1\30

work done by a in 5 days=5×1/30=1/6

work done by b in one day=1/20

remaining work which b has to do=5/6

work done by b in 5/6 days =5/6×1/20=1/24

work done by both of them=1/30+1/24=9 /120=3\40

so they will do the work in 13 days