If you are a student of general and OBC category then only you need 75% in board.If you are a SC/ST/PwD student then you need only 65%.The marks you need with your top five subjects only including Physics,Chemistry and Math.You can add up any two subjects like two literatures or one literature and one any other subject.With PCM you can calculate the other two subjects ,(among the three additional subjects) in which you are getting good marks.Best of luck!!