Yes you are right many students with poor academic record not selected in top b schools.in fact my friend is also not selected because her 10th percentage is not good even she scores 91 percentile in CAT.

Some colleges given weightage to CAT marks but some gives preference to academic record and work experience.

It is difficult for you to get in top b schools because of your 10th marks and no work experience may hurdle you.competition is very high in management professional you need to score 99 percentile to secure a seat in top IIMs and if not then make sure to get decent percentile to get baby iim's.

Get preparation tips and study material here

https://www.google.com/amp/s/bschool.careers360.com/articles/how-prepare-for-cat/amp