A, b, c can complete a work separately in 24, 36, and 48 days respectively. They started working together but C left after 4 days of start and A left 3 days before the completion of the work. In how many days will the work be completed ?

Answer 1

in 4 days, A&B&C did
4(1/24 + 1/36 + 1/48) = 13/36 of the job

In the last 3 days, B working alone did 3/36 = 1/12 of the job

That left A&B to do 5/9 of the work

1/24 + 1/36 = 5/72, so it took A&B 8 days to do their part.