Hi, hope you are doing great!

First of all, percentile indicates the the number of students whose percentile is same or below/above of you. It shows your rank that where you stand in from all the students. It is not possible to calculate marks from your percentile score.

E.g. if a student scored 70 out of 100 then he will be having 100 percentile because he is ahead of all the students.

So, it not possible to assume the marks by just percentile scores.

Hope it helps.

Thank you