Mythile,
That is hard to say and frankly, only PMI knows. Here is what I wrote in another article about PMP Myths:
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Myth 1: You need to score a 61% to pass the PMP Exam
No, while this was true at one time, it is no longer the case. Passing the PMP® Exam is no longer determined by the percentage of questions you answer correctly. It is calculated using a sound psychometric analysis. In essence this means that the harder questions are worth more than the easier questions. So you get a higher score if you answer more of the harder questions correctly and a lower score if you answer more of the easier questions correctly. The minimum score needed to pass is determined by the overall difficultly of your individual exam.
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But frankly, the only people who know for sure are PMI, and they are not saying.