I will try to explain the whole process but keep in mind that you must need 99+ to get a call from IIM A.

Now coming to the weightage part, for Initial Shortlisting 10% weightage is given to class 10th same with 12th and Graduation which means 70% is given to CAT score.

For the final Selection GD and PI comes into play. Now only 12% weightage is given to 10th. 12th and Grad. and 30% to the CAT score. Remaining is given to GD and PI.