Science

Hi
https://www.shiksha.com/science/ranking/top-science-colleges-in-india/101-2-0-0-0
https://www.shiksha.com/science/colleges/colleges-india
This is the exhaustive list for best colleges in chemical science. You should also specify the stream to know exactly which college is best, as it is also given by IIT BITS etc. which are the best.

See these links:
https://www.shiksha.com/bba/course/bachelor-of-business-administration-st-xaviers-college-ranchi-268505
https://www.shiksha.com/college/st-xavier-s-college-ranchi-10300/admission

Hi
https://www.shiksha.com/university/amrita-vishwa-vidyapeetham-Coimbatore-52263
refer this link to know about all the courses available in the college.

Hi
Your score is very low, you may not get a chance to get admission.
https://www.shiksha.com/university/ravenshaw-university-Cuttack-52514
https://www.shiksha.com/university/ravenshaw-university-Cuttack-52514/admission.

Try to clear your shortcomings by focusing on basics and then start practising by giving mock tests, it will give you idea about topic which you need to work hard and score most. Its all game of patience and practice. Work hard and overcome your shortcomings, I'm sure you will crack CAT/MAT or whichever exam you will appear for.

Hi
For M.Sc. Mathematics you have to do B.Sc. Mathematics first. You have to go through the prospectus of the course provided by the college to know more about eligibility etc.