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 choice from the following:	A) 15 days .	B) 12 days .	C) 24 days .	D) 13 days .	E) 16 days .

Rationale: 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 / 24 part . therefore the work can be finished by x = 24 days . ans : c
Answer: C