hi BALAJI,

             you can find out the minimum marks that is the cutoff marks in jee advanced from the below mentioned link:-

https://engineering.careers360.com/articles/jee-advanced-cutoff

and the cuttoff in jee mains 2018 from the below mentioned link:-

  https://engineering.careers360.com/articles/jee-main-cutoff   

And the eligibilty criteria for the plus two marks the Candidates must have secured a minimum of 75% marks in their qualifying exams in addition to qualifying in JEE Main 2017 OR must be in the top 20 percentile of their 10+2 board.

Hope this helped you.

best of luck.