If you are talking about jee mains.
Than it's depend upon the various factors like.
Number of students sitting in exam number of ST students.
On paper also weather it is easy ; medium; or hard.
Generally marks more than 310  is sufficient to get rank under 200.
It may vary depending upon the level of exam.
If you are talking about any other exam please mention.
Good luck.

Hiii

I would like to help you but you have not mentioned the proper details and i could not get any clarification in your question.
Which exam are you asking about please mention the name of the examination so that i can help you better in solving you query.

Thanks!!