B is 50% less efficient than A. How much time will they, working together, take to complete a job which A alone could have done in 15 days?
Choose the correct choice from the following answers:  A) 9 days  B) 11 days  C) 10 days  D) 15 days  E) None of these
Ratio of times taken by A and B = 100 : 150 = 2 : 3.   Suppose B takes x days to do the work.   Then, 2 : 3 : : 15 : x â‡’ x = (15Ã—3)/2 â‡’ x = 45â„2   A's 1 dayâ€™s work = 1â„15; Bâ€™s 1 days work = 2â„45   (A + B)â€™s 1 dayâ€™s work = (1â„15 + 2â„45) = 1â„9   âˆ´ A and B together can complete the job in 9 days.   9 daysnswer 9 days
<result>A</result>
B is 50% less efficient than A. How much time will they, working together, take to complete a job which A alone could have done in 15 days?