Birthday Twinning!

What's better than celebrating a birthday? Getting your BFF, sister, parent, BF, or whoever to celebrate it with you, twin style! 

It’s not very often that we meet someone that shares the same birthday as us. In the rare case that we do meet those people, it’s always exciting to share the celebration with someone. Whether you share it with an acquaintance, friend, or family member it somehow brings a bond between two people closer.

What are the odds?!

One person has a 1/365 chance of meeting someone with the same birthday.
Two people have a 1/183 chance of meeting someone with the same birthday. But! Those two people might also have the same birthday, right, so you have to add odds of 1/365 for that. The odds become 1/365 + 1/182.5 = 0.008, or .8 percent.
Four people (lets call them ABCD) have a 1/91 chance, but there are 6 possible combinations (AB AC AD BD BC CD) so the probability becomes 1/91 + 6/365…and so on.

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