Hi Ram,
To calculate the following, I have used our JEE-Mains 2020 percentile calculator. With 145 marks, you are expected to get a percentile of about 98.63- 98.83 with a rank of 10610- 12760. You can calculate for yourself using this link:
JEE Main Rank Predictor - Know your expected IIT JEE Main 2020 Rank by ...
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