Just like the 25 answers correct, just get 100 correct, some tips:
If you're going for accuracy, take your time answering question to make sure you get the correct one.
Safety's are helpful, if you may have a question you don't know, use a safety, it adds to your total and give you one free correct question (i personally use my safeties every bonus question)
Unless your a genius and get every answer correct, if should take you around 5-10 extended plays to unlock this.
To check how many correct answer you have, hit the right trigger and move until you see something along the lines X/X
Number of correct question/number of question asked