Direction: The following questions are accompanied by two statements (I) and (II). You have to determine which statements(s) is/are sufficient/necessary to answer the following question.

If ‘x’ boys can complete a work in 10 days and ‘y’ girls can complete the same work in 15 days. Find the number of days taken to complete the work by (x – 4) boys and (y – 3) girls together.

Statement I: If the Ratio of efficiency of boys to girls is 3 : 4 and (x + y) = 18.

Statement II: If x = 2y, then the number of days taken by all the girls is half the number of days taken by all the boys.