If you are belongs to General Category students needs 75% in aggregate. It depends on the cut-off marks. No. of applicants scoring more than you. If you are SC or ST, then there is priority preference. It all depends on the merit or Percentages how many students scored higher than you if there are 50 students who scored more than you then the chances of selection become too lesser. That's why all should depend over the 10+2 percentage merit cutoff.