Dear Aspirant !!

Hope you are doing well ! On the 80 percentile you will get around 50-55 marks ,it varies from shift to shift and depending on your shift difficulty level it can vary ,but on an average you will have 50 marks for 80 percentile.

https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://engineering.careers360.com/articles/jee-main-marks-vs-percentile&ved=2ahUKEwi4--7o1sSFAxVuffUHHUSSCzYQFnoECB4QAQ&usg=AOvVaw1puMET2kwWOALxmTAQupVE .

You may visit this link for marks vs percentile comparision.

Hope it helps you!

Thanking you !