CBSE 10th

Higher the percentage, better chances you have but the minimum percentage required is 80. Apart from that you need to have a high score in SAT/ACT and TOEFL/IELTS to get admission in USA.

This is something that varies from school to school. You should check with your teachers about the criteria that your school follows.
According to me, you should get PCM at B2.

That depends on your reservation category, if any. You can refer to this URL to get an answer :
https://www.shiksha.com/mba/resources/iim-call-predictor

Hi Nishant, there are plenty of colleges. It is difficult to answer which is the best as numerous colleges are located across the entire country. Please go through this site which lists out all the colleges location wise.
http://www.australianuniversities.com.au/colleges/list.php
To further help you out here are the best student cities - Melbourne, Perth, Adelaide, Brisbane, Sydney while few of the quite affordable ones include Wollongong, Canberra and Hobart. Look for colleges in and around these places.
Regards

Dear Deepika, 10th scores come into picture only in case of a tie. So if you have good score you must be good to go. Best Luck.

I don't think you will get an interview call from IIMA. IIMs put a individual score cutoff of 60% for all past academic performance. If you are below that, then you will not be considered for the interview. However IIMs call top 100 students in all streams for the interview, irrespective of their academic performance. Hence if you can secure top 100 rank in CAT, you will get a call from IIMA.

yes u can do it