The Birthday Paradox

I am a Dude who loves numbers (I capitalize "Dude" because I rule). However, I hate math. This may confuse you, but numbers in and of themselves propagate patterns, and generally determine how life runs for us. Math, on the other hand, shows little to no logic to anyone, save the privileged few who understand how stuff like the Birthday Paradox works.

Say you're in a room with 39 other people. What are the odds, would you say, of you and another person having the same birthday? Pretty low, right? You'd say that in order to be sure, you'd have to have 366 people (number of days in the year, plus one), right? And that with only 40 people in the room the odds are around 10%, right? Wrong, wrong, wrong. With 40 people in the room, the probability is over 90%. Whazza? Doesn't seem right, does it? Even stranger, if there are sixty people in the room, the odds increase to above 99%.

Strictly speaking, it's not actually a paradox. All the same, it blows minds in much the same way. You can find an exact explanation of the problem here. This article is good for a laugh, too.