CAT

Maharashtra MBA-CET Complete Book by Chandresh Agrawal
Target MHCET 2018 (MBA / MS) 2018 Past (2007-2017) + 6 Mock Tests by Odisha Experts
MH-CET (MBA/ MS) Entrance Guide by Odisha Publications
Quantitative Aptitude for Competitive Examination by R. S. Agarwal
Maharashtra CET-MBA 2018 with Solved Papers & Mock Papers by R. K. Jha.

For admission into any MBA college, they will check your graduation marks. Most of the college keep minimum 60% criteria.

Admission into MBA without CAT/open test will not lead you to a good college and also will not be of much utility from career perspective.

For seeking admission into top 20 MBA colleges one should try and score more than 90 percentile.

Yes, of course. There are two major sections of aptitude and reasoning that comprises of 50% of the CAT's syllabus and it has nearly 80% of mathematics in it. So definitely half of the syllabus would become easier for you.

Hi Yash,
I had inquired in many coaching institutes of Mumbai for preparation of CAT. According to me, Endeavor coaching and TIMES were the best institutes for CAT preparation.

Yes, Somaiya accepts CAT score for MS course under All India Seats Quota through DTE's CAP rounds.

Top 5 CAT coaching institutes in Delhi are mentioned below:
Alchemist Institute. TIME Institute. Career Launcher. IMS Learning Resources. AnkGanit.