Hello Akash

We can not calculate marks from the percentile score  because percentile is the relative score which depend upon the number of students who score more than you and total number of students.

Example:

If you score 200 in the test ;and number of students who score more than you is 6 out of total 10 ; your percentile will be 40 .

Now another case you score 260 marks ; but the number of students who score more than you is same 6 out of 10 total; percentile remains same.

So percentile is a relative score which is used to make all the exam slots equal.

Percentile = (total students- number of students who score less than or equal to you)*100/ total number of students.

Good luck.