Question 314865
A can finish a work in 6 days whereas B can finish the work in 9 days.If both of them work together,what is the probability that the work will be finished on third day?

A --> 1 job / 6 days = 1/6 job per day
B --> 1 job / 9 days = 1/9 job per day
A + B = 1 job / (1/6 job/day + 1/9 job/day)
A + B = 1 job / (9/54 + 6/54 job/day)
A + B = 1 job / (15/54 job/day)
A + B = 1 job * 54/15 days/job = 54/15 day/job * job
A + B = 18/5 days = 3.6 days
takes A and B 3.6 days to do it together,
if they had finished on the first day answer would be <= 1,
if 2nd day answer would be >1 and <= 2,
if 3rd day answer would be >2 and <= 3,
so they finished on the 4th day, so probability that work will be finished on the 3rd day is 0