There is no such criteria that scoring so much mark swill get you 100 percentile. But one thing which can you be definitely sure about is scoring 300 out of 300 will definitely get you 100 percetntile.

Because the percentile is calculated as

%ile = (No. of students scoring marks less than or equal to a candidate)/(No. of total students in that slot) * 100

As you can see, there is no particular marks which can get you 100 percentile.

It depends on the relative performance of a candidate, difficulty of the question paper, No. of students appearing in that slot.