Questions on left the job

Ashish, Binay and Joseph can do a job in 20, 30 and 40 days respectively. The three started the job together, Ashish left the job 4 days before it was completed and Binay left the job 3 days before it was completed. In how many days was the job completed?

30 men can complete a job in 40 days. However, after 24 days some men out of the assigned 30 left the job. The remaining people took another 40 days to complete the job. The number of men who left the job is

15 persons have taken a job of digging a pond in 20 days. 5 persons have left after 10 days. Again after 5 days 5 more have left. How many days would be required to complete the job ? (a)55 (b)25 (c)35 (d)45