How many Multiple Choice questions must I answer to get a 3 on the AP Biology test?

I'm not exactly sure about the AP Bio test, but I know that for the AP Chem test, you can answer just 40 and get a 5. It all depends on your raw score. Just make sure you don't answer any questions you know you have no knowledge on, and you should be all right.

Ok, so i'm taking the test tomorrow too, and my teacher has been doing the formula with us for a while.  If i remember it right, I think you need a score of at least 35 questions to come off with a 3, and that's after subtractions from missed questions.  

and don't worry too much about how you do on the test tomorrow, that only makes you do worse (i know it's hard not to do cause i'm trying not to freak right now either...).  Just remind yourself that even if you totally bomb the test tomorrow, you don't have to share your scores with any college.  and plus it's more important to colleges that you just took the test more than your score.  Thinking that's been helping me.

Good luck tomorrow!

I know the test is over, but don't worry too much.  AP Exams are curved, meaning that the top 20% of the scores nationally receive a 5, the next 20% a 4 etc., so the exact grade to get a certain score changes every year.
    This is the fairest way to grade the tests, because if there is an error in the test itself, it won't effect anyone's score (if everyone gets the same unclear question wrong, then it won't effect the grades in the curve).
Good luck!