X and Y together can completes a work in 12 days and Y complete the same work in 24 days. Then the number of days X required to complete the work will be?	Choose the correct answer:  A) 15 days.  B) 12 days.  C) 24 days.  D) 13 days.  E) 16 days.
X and y complete in one day =1/12 part, y completes in one day=1/24 parts. Therefore X alone can do in one day =1/24part. Therefore the work can be finished by X = 24 days. Ans: 24 days.
<result>C</result>
X and Y together can completes a work in 12 days and Y complete the same work in 24 days. Then the number of days X required to complete the work will be?