Mary can do a piece of work in 11 days. Rosy is 10% more efficient than Mary. The number of days taken by Rosy to do the same piece of work is?  Choose the correct choice:
A) 10  B) 15  C) 20  D) 25  E) 30
Ratio of times taken by Mary and Rosy = 110:100 =11:10   Suppose Rosy takes x days to do the work.   11:10 :: 11:x =&gt; x= 10 days.   Hence, Rosy takes 10 days to complete the work.   10nswer: 10
<result>A</result>
Mary can do a piece of work in 11 days. Rosy is 10% more efficient than Mary. The number of days taken by Rosy to do the same piece of work is?