my 10th(84),12th(60) and grad score are (82,72,78) of 3sem. I'm pursuing BCA right now and left with one year academics.. im also preparing for CAT entrance exam.. also I got no work experience.. am I eligible for IIM-B 2021 batch??

Pooja, you have impressive Academic track record except for 12th. IIMs shortlist candidates for the interview stage based on their own criteria, which may be independent of each other. The process may include Written Ability Test, Group Discussion, and Personal Interviews. Performance in the CAT examination is an important component in the admission process. IIMs may additionally use other factors such as the previous academic performance of the candidates, relevant work experience, gender and academic diversity and other similar inputs in shortlisting and ranking of candidates at various stages of the admission process. The processes, academic cut-offs and the weights allocated to the evaluation parameters may vary across IIMs. Coming to IIM Bangalore, their 2019 cut offs have been as follows:

And then, for all the Candidates shortlisted, the 10th and 12th board results are initially adjusted by dividing each such score by 90th percentile score of that board. And then an adjusted score is calculated for the Bachelor's degree for each of the candidates based on the final scores obtained by the candidate are used for the Bachelor's degree and professional degrees. For example,

CAT = 40
10th board = 20
12th board = 10
Bachelors = 20
Gender Diversity = 2
Work Experience = 8
The 40 points for CAT are derived from the performance in each of the three sections as follows:
Verbal & Reading Comprehension - 14 points
Data Interpretation & Logical Reasoning - 16 points Quantitative Aptitude - 10 points.

Work experience carries 8 points but if you can manage to score more than 95 percentile in CAT, you might have a chance at IIM Bangalore.