Hello Kalyan!

I don't think you can use youe JEE mains 2018's marks you write JEE advanced 2020. I guess you have to write JEE main again on 2020 and then try for JEE advanced. 

Moreover, there is no harm in writing JEE mains once again if you are preparing for JEE advanced. You might end up scoring more!

All the best!

hi Kalyan,

yes you can write jee advanced in 2020 but remember it would be your last attempt as according to the NTA rules a candidate is only allowed to attempt the paper thrice including the year in which he passed his 12th

and the exam is conducted twice in a year in january as well as in april which means a candidate can give the exam a maximum number of six times.

hope it helps :)