Archive for category Mathematics

The Skeptic Santa Problem

This Saturday is the Merseyside Skeptics Christmas Party (at the View Two Gallery on Mathew Street from 7pm, everyone is welcome).  And as part of that event, we’re planning our own version of the Secret Santa game that some of you may be familiar with.

This is how it works: each person who wants to play the game brings a gift, to no more than £5 value.  Each gift is exchanged for a raffle ticket.  At the end of the night, raffle tickets are drawn and people are awarded their gifts.  You must have a ticket to get a gift, so you only get a gift if you gave a gift.

Lovely. Though there are a couple of problems.

First, we don’t want people getting their own gift back.  It’s not particularly nice, and for less than a £5 value, it’s probably some piece of gift-wrapped tat anyway. You brought it to the party because you wanted to get shot of it, you don’t want it back.  So that’s problem number one.  Problem number two: we don’t want people to be able to game the system.  By that we mean, we don’t want people to be able to engineer things so they can guarantee  their gift goes to a particular person, or a particular person’s gift goes to them.  It has to be fair.

We have come up with a few solutions to this problem. Some mathematical, some empirical, some just plain daft.  Most of them are flawed in some way, but we think we have one which works.

What solutions can you come up with?  We’ll publish ours after the party.

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