A can do a certain job in 16 days. B is 60% more efficient than A. How many days does B alone take to do the same job?  Choices
A) 11 1/4 days
B) 8 days
C) 5 days
D) 10 days
E) None of them
Ratio of times taken by A and B = 160 : 100 = 8 : 5.   Suppose B alone takes x days to do the job.   Then, 8 : 5 :: 16 : x = 8x = 5 x 16 =x = 10 days.   Answer is 10 days.
<result>D</result>
A can do a certain job in 16 days. B is 60% more efficient than A. How many days does B alone take to do the same job?