For BBA at GIBS, it's not super tough to get in. You need around 60% in your 12th, and there's no big entrance exam. What really matters is how you do in the interview and group discussion—they want to see your confidence and attitude. So if you prepare well and show who you are, you have a good chance.
For PGDM, it's a bit different. You need a graduation degree with at least 50%, and you should have scores from exams like CAT, MAT, CMAT, or XAT. Then, you'll also have to clear a group discussion and interview. Even if you have around 70% in your degree, you can get in if your entrance scores and interview go well. It's about your ov