Well to keep it simple its just like a percentile system that is followed by CAT. It is a score that you obtain compared to the rest of your classmates. For example for a 100 marks paper if the highest score in the entire class is 75 then the grading for the rest of the students will be done based on the highest score. Although it is not followed in 1st year as far as i know but during your core subjects grading, Relative marking is taken into consideration.
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