MHT CET

There are plenty of E books, but rather than using online e-book, go for offline books for practice. And, for online, give some mock tests for MBA CET and speed test on aptitude and reasoning. I will suggest you to prefer Arihant Publication and ask for the IBPS Clerks Mains model paper set and do practice from it, as the MBA CET is conducted by IBPS. The question level for Clerk Mains and MBA CET is same or if you don't find some good test series for MBA CET go for IBPS Clerk Mains. And, don't forget to go through IBPS Clerk current year paper, which already happened in January, as lots of reasoning and aptitude pattern for both are around same.

Please check for eligibility criteria for this entrance exam provided below. You should be able to gauge whether you require a GAP certificate from the eligibility criteria mentioned below. as per my knowledge, GAP certificate is not required to appear for this exam.
MAH-CET 2018 Eligibility:
Here's the eligibility criteria for MAH-CET:
1) Candidates must have a Bachelors degree in any discipline from any recognised university with a minimum of 50% marks, and at least 45% in case of reserved candidates.
2) Final year students can also apply.
3) Candidates appearing for CAT / GMAT / CMAT /MAT February / XAT/ ATMA are considered to be eligible for admission against the All India Seats subject to the fulfillment of eligibility criteria. Such candidates need to fill online application form according to the schedule.