Hi Anupamt,
On your Official Score report, you'll receive a number of different pieces of data.
A percentile is just a measure of "where you are in line" compared with the other people who took that Test. The scoring algorithm on the Official GMAT is far more complex than most people realize (and is based on the 2 Scaled Scores you receive in the Quant and Verbal sections). The calculation involves a number of different factors, including which questions you got correct and incorrect, the relative difficulty of the question, whether you were expected to get it correct or not, whether it even counted or not (some questions are 'experimental' and are worth 0), the 'strings' of answers, if you ran out of time and left questions unanswered, etc.
As such, you cannot look at a Scaled Score and know "that's how many questions I got correct."
Are you planning to retake the GMAT?
GMAT assassins aren't born, they're made,
Rich