I am assuming you are from general category. Based on your overall academic profile, you will need to score atleast 99.9 percentile to get a call for the next round.

All the best!

Yes you can get the seat. In each IIM there in an individual selection process and therfore is most of the IIM's academic scores are a must thing and a strict aspect to judge.

Say in IIM A, If you have 90 percent above in your past academics say in 10th, 12th and even graduation then you can get 10/10 (scaling out of 10) and it shall differentiate in other IIM's.

Like in top 3 IIMS A,B and C, check the selection process below and know the weightage of the exam, GD/PI/WAT and past academic records in the link below:

IIM A Selection

IIM B Selection

IIM C Selection

Aim scoring above 98-99 percentile to get the chances of admission in top management colleges.

All the best!