Percentile is a way of giving scores popularly used for most of the MBA Entrance Exams.
In statistics, a percentile (or centile) is the value of a variable below which a certain percent of observations fall. For example, the 20th percentile is the value (or score) below which 20 percent of the observations may be found.
If your percentile is lets say, 80%, it means, 80% of the total number of candidates have scored less than you.Or you are above 80% of the canditates for that particular score.
For MAT, a total score of (marks not percentile) 600 and above is good enough to get admission into a good BSchool.
But mostly , the colleges taking MAT score come under Tier-2 , there might be exceptions, of which am not sure.