Hi Ajit,

If you want to score 98 percentile  in JEE Main Examination 2020, then your are required to score 140 - 150 marks in the JEE Main Exam. Please note that these marks can vary as number of appearing candidates tend to change.

Refer here for more info - https://engineering.careers360.com/articles/jee-main-marks-vs-percentile

Feel free to ask doubts in the Comment Section.

I hope this information helps you.

Good Luck!

Hello.
it becomes quite difficult to predict marks from your JEE mains percentile as it is your normalised score which depends upon the number of candidate who get less than or equal to your marks and total number of candidates appeared for the examination and marks scored by toppers, this data changes every year at that time generating an exact marks on a particular percentile becomes difficult still you can have an idea through the provided link where within a particular percentile range your expected marks can be seen.
https://engineering.careers360.com/articles/jee-main-marks-vs-percentile
Best of luck.