## Mathalicious Post: Most Expensive. Collectibles. Ever.

Hey y'all.  My most recent post on the Mathalicious blog has been live for a while, but in case you missed it, I’d encourage you to go check it out!  Consider it a Simpsons themed cautionary tale for collectors on a budget.  Here’s a sample:

One of the more recent trends in the world of Simpsons memorabilia is the advent of the Mini-Figure collections, produced by Kidrobot.  Each series (there have been two so far) consists of around 25 small Simpsons figures, each with his or her own accessories.  The figures cost around $10 each ($9.95, to be precise), so an avid collector would need to spend something like \$250 to complete each of the two collections, right?

Well, not quite.  When you buy one of these figures, you have no idea which one you’ll get, because the box containing the figure doesn’t indicate what’s inside.  All you know are the probabilities for each figure, and even those are sometimes missing…

Given this information, here’s a natural question: how many of these boxes should you expect to buy if you want to complete the set, and how much will it cost you?