In theory, the answer is unknown, this is because of the complicated way PMI scores the PMP. They do not give you a score, you either pass or you fail.
In practice, however, most people say that you have to get 62% of the questions right in order to pass. So we have 200 questions, and out of these questions, there are 25 pretest questions that are not graded, so you have to get: 175 * 62% = 108 questions (some say 106) right, which means that you can get as many as 92 questions wrong in order to pass (assuming you get all the 25 pretest questions wrong). That's a lot! By the way, you do not know if you're answering a pretest question (it doesn't show), so you may have more than 108 questions correctly answered, but still fail, as you might have correctly answered pretest questions which don't count anyway. This means to be on the very safe side, you have to think that you can only get 67 questions wrong.
I know, it's tricky and confusing, but not that hard.