I AMIT RAJ . I SECURED 62% IN CLASS 12 WILL I GET GOOD PLACEMENT ACCORDING TO MY ACADEMIC PERFORMANCE IF I'LL GET AROUND 85% IN CAT

Placement is not much dependent on your academic score. It depends on your overall profile so yes you can get good placement provided you work on your profile after getting into MBA

If you can fetch 85% in CAT, you may get good tier-II B-school which is also dependant on your GD-PI score ( along with CAT score). Placements are Dependant on your performance in B-school, your academics and your overall personality. So, it is very difficult to predict about your placement on this