Santacon 2009 - Astoria, Queens NYC

Photo, Santacon 2009 – Astoria, Queens NYC by kstraw2 on Flickr

A friend texted me today and asked what the chances are of a group of seven people picking names in their office Secret Santa without anybody choosing themselves. A clean draw, so to speak.

Now, there are a number of ways that you can try and work this out, but I think the easiest to follow is by thinking of the problem in terms of the number of permutations of the possible outcomes.

In my friend’s office, the first person to draw a name out has 7 possible names to choose from, then the second person has six names, the third person has five names and so on.

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