Hi

It is quite difficult to make prediction as marks vs percentile vs rank keeps changing every year depending upon a number of factors like

*Number of students that appeared in the exam

*difficulty level of the JEE main examination for different shifts

*Kind of marks obtained by the students in the exam etc

But yes,

To  get 98.5 percentile you should try to get at least around 160- 165 marks

For example,

As per our predictor with 160 marks, Overall Percentile considering  that the question paper is of moderate level  will be around  98.0 - 99.06 percentile

You can check the same at

To score well,you should focus on your preparation ,go through previous year question papers ,mock test papers and to help you in your preparation we have jee main knockout out for you, for which  link is provided below

https://learn.careers360.com/knockout-jee-main

After your exam,

To have a personalised report on your chances of getting a college you can go through our college predictor, it will give you complete list of colleges which you can get on the basis of the category you belong to,  your home state, your gender etc, the link for  jee main college predictor is provided below

https://engineering.careers360.com/jee-main-college-predictor?icn=QnA&ici=qna_answer

Thankyou