The basic admission criteria at BIT mesra consists of JEE mains score ,hence along with 12th board exam score you will also need a good JEE mains score. It has also been decided that 50% seats will be given to the eligible aspirants who have qualifications from Mesra/ Ranchi .Talking about the cutoff of 2020 there are multiple engineering courses available and hence in the special round 1 the admission started from rank 2980 that is for their computer science engineering course and it ended around rank 48495 for their production engineering.

All The Best!