• Candidate must hold a graduate from any recognised university
• Candidates who are in final year are also eligible
• general category should have 50%  and there is 5%  relaxation for SC/ST i.e, you need 45% minimum.
• There is no age restriction
• There are no number of attempts

Dear Moorthy, CAT is an entrance examination for admission to MBA and PGDM courses which are post graduation courses and the highest qualification required is a Bachelor's degree. With 12th as your qualification, you cannot appear for CAT. You either should have completed your Bachelor's degree with 50% or should be in the final year of Graduation to be eligible for CAT. It is 50% for General Category and 45% for Reserved Categories.

Hey!There

No,you can't appear in CAT EXAMINATION after passing 12th board EXAMINATION.Because only appearing students or students who passed Graduation are elligible for CAT EXAMINATION..

To know elligibility criteria of CAT 2020,hit below link:

https://www.google.com/url?sa=t&source=web&rct=j&url=https://bschool.careers360.com/articles/cat-eligibility-criteria/amp&ved=2ahUKEwj53sKu8IflAhVi7HMBHfXqC4gQFjAPegQIBBAE&usg=AOvVaw1aL49Dq1TPG_GKlvbaQ_Jc&ampcf=1