One of the important aspects of preparing for your PMP Certification is going through a process of answering a series of sample questions that are purposely meant to test your readiness for the big day. As you may already have realized, studying for the exam requires a lot of work, including taking numerous sample tests to find out if you can cope with the question format of the actual exam.
This is why we recommend that you take at least 1,000 PMP sample questions. This means that you simulate a complete 4 hours exam to gauge your ability to finish the actual exam on time. As a general rule of thumb: If you are able to correctly answer at least 85% or more of the practice questions on your first try, then you are ready for the PMP Certification Exam.
It is important that you take these sample exams as they prepare you for the rigors of the exam day, and the type of questions that will be asked. It is even possible that you will encounter questions similar to the ones on your sample tests during the actual exam.
Remember that PMI does not release the actual number of questions that you need to answer correctly in order to pass. They are very vague about it and you can read up on the exact scoring system in the PMP Handbook. The best that you can do is to take a shot at practicing with sample exams. That helps you to get prepared.