IIM

At least 95 percentile is needed.

This question is really vague. It is better you do research a bit about the courses and then ask questions related to it.

Hi Aarti,
Getting into IIMS depends a lot on your CAT score, as well as how you do well in interviews and What/GDs. Given your Class X and XII score, I would say you have a decent chance to get into one of the old IIMS, if you do well in CAT. Also, you haven't mentioned your graduation score, which also plays a role in the selection process. Good luck with your preparations and I hope you do well.

For IIM, CAT is must for admission. But, for rest of top B-School, you can give different entrance exams along with CAT like SNAP for Symbiosis University, XAT for XLRI-Jamshedpur, and lots of top B-School also accepts the score of entrance exams like MAT CMAT ATMA. So, choose the college first, and then prepare for entrance exams that accepted by that college.

Go through the IIM call predictor below for details:
https://www.shiksha.com/mba/resources/iim-call-predictor.

Overall, the cut off of IIM Ahmedabad is 80 percentile & above. Quantitative Aptitude (QA), Data Interpretation & Logical
Reasoning (DILR) and Verbal and Reading Comprehension (VRC) in 70 percentile for general category.

Overall, the cut-off of IIM, Ahmedabad is 80 percentile & Quantitative Aptitude (QA), Data Interpretation & Logical
Reasoning (DILR) and Verbal and Reading Comprehension (VRC) in 70 percentile.

Just go for the maximum. But honestly, 98+ percentile can give you call for all IIMs, given that the profile is good.

You have chances of getting IIMs. Some of the IIMs are not that much famous as other colleges are like IIFT, Symbiosis, JBIMS so you can get IIMs but not IIM-A,B,C you can get some better colleges than other IIMs.

Yes but for getting top colleges you really need to score well in CAT at least above 95 percentile for getting call from top colleges and above 98% to getting call from IIMs.