Hey.

The cut off for falling in the top 20 percentile of Maharashtra HSC in 2018 is-

General- 361

OBC- 362

SC-343

ST- 340

PWD- 340

For calculating top 20 percentile out of 500, you can to consider the marks scored in five subjects - (1) Physics, (2) Chemistry, (3) Mathematics, (4) A language and (5) Any subject other than the above four, is taken into account.

Best of luck!