How many people have to be in a room for there to be a 50% chance that at least 2 people have the same birthday (there are 366 possible birthdays (Feb 29) and each birthdate is equally likely to occur). Note: Approach it from the perspective of adding one person to a room at a time and how the universe changes each time someone new comes to the room. Yes, you can all do this. If you want an A, you need to at least