The Omnifarium - Sudoku

Notice

I am no longer posting new puzzles to this blog. For all of my Sudoku puzzles, old and new, please visit Sudoku in another section of this website. I will still create and offer new puzzles, in batches of a couple of hundred, once a week or so.

Sudoku #23

Category: Sudoku
Fri, 15 Jul 2005, 19:10

What's special about the number 23? If you have a room full of 23 people, chances are better than 50:50 that two of them will have the same birthday. This might seem surprising, but sometimes intuition fails us.

Consider a room with two people. There's just one way to have a pair of people with a common birthday. But with three people, there are three ways. With four people, there are six possible pairs, and with five people, there are ten possible pairings. As you add more people to the party, the possible ways to have a common birthday rises at a much faster rate. I won't show the math here since someone else does a better job explaining the probabilities involved.

But solving Sudoku has nothing to do with probabilities. There's just no point in trying to use probability theory when solving a Sudoku puzzle. All possibilities for a cell must be considered equally valid until eliminated through ruthless logic.

Todays puzzle, like all others here, can be solved analytically. It might not seem like it, though, if you get stuck. If you're not aware of all the solving techniques I use, you may well get stuck with this tricky one!

Hans

path: /Sudoku | permanent link to this entry