Passing PMP is a tough task. it is tough because this requires a consistent effort for around 120 hrs. You can do this 2 hrs for 60 days or 4 hrs for 30 days. However in my experience , passing PMP depends upon the number of practice exams you take and the good news is that these are freely available. Around 70%  of the questions follow the methodology in these sample questions. Targetting around 80% in these sample exams guarantees the success.These are the sites where these sample tests are available.