Hey abhay

You can not find out the exact marks from percentile because percentile is relative score of you among all other candidates.

Like in a test 10 students score as:

1;2;3;4;5;6;7;8;9;10 out of 15 marks 

Than the percentile of student who score 10 marks is 100 and who score 9 is 90 

Another case :

2;3;4;5;6;7;8;9;10;11

Now student who score 11 got 100 percentile 

And scorer 10 will get 90 percentile.

I think you got what i wanted to say.

Good luck