[ A can do 75% of a job in 9 days and B can do half of the job in 8 days.If they work on it together, then in how many days can they do half of the job? [ a) (40)/(7), b) (24)/(7), c) (7)/(2), d) (9)/(2)]]

b) 24/7days

24/7 days

A completes the work in 12 days, so A's 1 day's work = 1/12
Similarly, B completes the work in 16 days, so B's 1 day work = 1/16
(A + B) 's 1 day work = 1/12 + 1/16 = 7/48
So, together they will complete the work in 48/7 days
Time taken to complete half the work = 24/7 days