Heya Amarjyoti,
The minimum cutoff to pull of an exam depends on various factors like the difficulty of the exam, the no of participants etc, so we cannot give you a pin point answer as such. But you can get a slight idea by checking out various estimates published online by various websites. As of 2017, it was 50 percentile for general category. You can check out official website for more precise info.
Regards and best wishes.