A can do a certain job in 18 days. B is 60% more efficient than A. How many days does B alone take to do the same job?  Choose the correct choice from the following choices
A) 11 1/4 days  B) 8 days  C) 5 days  D) 9 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 :: 18 : x = 8x = 5 x 18 =x = 11 1/4 days.   11 1/4 daysnswer is 11 1/4 days.
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A can do a certain job in 18 days. B is 60% more efficient than A. How many days does B alone take to do the same job?