Photo: surlygirl

Situations arise from time to time where you are in a room with a whole bunch of strangers. They key to making friends and the opposite sex swoon? Probability.

What are the odds that two people in the room have the same birthday? Memorize some of these numbers so that you can spout them off, I guarantee you will be the coolest guy in the room – 9 people = 10%, 13 = 20%, 15 = 25%, 18 = 35%, 23 = 51%, 57 = 99%, 366 = 100%.

It’s important that you mention the assumptions before your new worshipers start poking holes in you numbers – random distribution of birthdays, no leap years, no twins, etc. Then you can go into what is interesting – with only 23 people in the room, odds are two people share a birthday. It only takes 57 people to jump to 99% probability, but to get to 100% you need to have 366 people.

Now to really make their mouths drop. How many people would it take for the odds to be in your favor for someone having the same birthday as you? 253. They may question you because this is much higher than 365/2, but stick to your guns and point out that two of the other people could have the same birthday. How many people would it take for two to likely have a birthday within a week of each other? Only 7. Ya, but a random distribution is a hell of an assumption. Oh really? Actually the odds are slightly more in your favor because birthdays tend to clump – summer babies, C-sections aren’t on weekends, and so on.

Here’s one to set up on a tee for them: what are the odds that two people have the same half birthday? If they can figure this out, you may just have found your soulmate.