The cut-offs vary every year depending on certain factors and they change category wise also. Generally there's not much difference between the general category cutoff and the obc category cut-off. You need to get more than 75% in the entrance exam to be considered eligible for admission and get a seat. But, it's better if you get more than 85%. The marks in the written exam are given more importance and the rest 15% marks are divided into GD-PI. Hope this helps.