MBA Entrance Exam

To score 80 to 90 percentile in CMAT exams you need to study from TIME/IMS MBA coaching institutes which can give you a basic concepts about CMAT preparation technique in easy way.

Although there hasn't been an official confirmation on this, but following the previous year trends, CAT'16 is most likely to be held in the month of November'16.
So, that gives you roughly 9 months for preparation, if you are going to write CAT'16. For a month-wise preparation methodology for CAT'16.
All The Best.

https://www.shiksha.com/top-mba-colleges-accepting-mat-score-article-6056-1
Complete list of top tier MBA coll with MAT acceptance has been given above along with paper pattern for MAT.

It depends on what package you take as its Your ability to cope up with the syllabus. Generally it can be 3 months to 15 months.

Dont know about CAT, but JEE and NATA are the scores accepted by many university, some accept JEE, and some NATA only.

It shall have four sections into Quantitative aptitude, Logical Reasoning, General Awareness, English Reading and Comprehension.
http://www.amity.edu/admission-procedure-domestic.aspx

https://www.shiksha.com/mba/ranking/top-mba-colleges-india-accepting-mat/2-2-0-0-306
It is completely beneficial as candidates appearing shall be very less than others.

https://www.shiksha.com/mba/exam/mat
Complete details provided above for paper pattern and free mock exams.