Hey.

The BMS entrance test for St. Xaviers includes the Sections of General Knowledge, Current Affairs  Data Interpretation and Basic Mathematics  Language Skills  Reasoning/ Critical Analysis & Creative Thinking.

To prepare for GK & Current affairs –you should Read the newspaper on daily basis, stay updated with TV news channels for Current affairs as well as Verbal ability. . You can also refer to  current affairs magazines like Readers Digest, Competition Success Review, Pratiyogita Darpan etc.

 You can refer to the NCERT books from 9th to 12th class of  Economics, Stats, General Studies to brush up your concepts.You can use word power made easy for vocabulary. Practice writing short essays. 

Make sure you practice the previous year questions or sample papers so that you're aware of the pattern and know how to manage your time.

Best of luck!