CAT

Dear aman jaggi. there is no specific syllabus for CAT. that changes its patterns. but there will be quantitative aptitude, general English, general knowledge questions will be asked more. therefore practice previous papers. that will help you out. further take at least short tem coaching for CAT to get understanding of the same. all the best.

If you want top tier college like IIMs, you have to score 90percentile + and if you want to do MBA from decent B-School, you should at least have 80percentile + score in CAT.

You should at least have 50% in graduation for appear for CAT.

maximum reputed company consider 2year gap for a strong reason.

Yes Sona you can avail education Loan form Banks.

Aamir, you can. To appear for CAT/XAT/MAT etc  student needs to have 50% in graduation. But eligibility criteria varies for various Management Institutes or Universities, they can take different %age in graduation along with CAT/ MAT/ XAT scores. 
Another way of admission is entrance tests of individual Management Institutes or Universities.
Higher you score in CAT etc more easy for you to get admission.
You can check the websites of some universities for more details.
Good luck.

Go for CAT n then you will have any other choices open to decide upon.Take tutorials for the preparation

You can check out this link for good coaching institutes in UP for CAT exam:
https://testprep.shiksha.com/cat-entrance-exams-coaching-classes-in-uttar-pradesh-categorypage-14-47-809-0-0-1-126-2-0-none-1-0#cateSearchBlock

Dear upanand, any of one competitive exam is required to get into university or either you can write KMAT exam.