Four (4) hours are more than enough to answer 200 questions on the PMP Exam. You have 1:12 min for each question. Since, all questions are multiple choice questions, it usually takes less than a minute to answer the questions. Most people complete their first pass of all 200 questions within three (3) hours, and the remaining time is spent in reviewing the marked questions.
Tip: Try not to spend more than a minute on any question during the first pass. Mark all wordy questions for review and answer them on the second pass.