Author Archives: possiblywrong

Iterative Poohsticks

The game of Poohsticks was invented by Milne and appears in one of his books, where Pooh and Christopher Robin each simultaneously drop a stick into a river from the upstream side of a bridge.  The winner is the one … Continue reading

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Horse race puzzle

Introduction This post is part pedagogical rant, part discussion of a beautiful technique in combinatorics, both motivated by a recent exchange with a high school student, about an interesting dice game that seems to be a common introductory exercise in probability: … Continue reading

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The hardest 24 puzzles

Introduction Once again motivated by a series of interesting posts by Mark Dominus, a “24 puzzle” is a set of 4 randomly selected numbers from 1 to 9, where the objective is to arrange the numbers in an arithmetic expression … Continue reading

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Anagrams

Introduction This was a fun exercise, motivated by several interesting recent posts by Mark Dominus at The Universe of Discourse about finding anagrams of individual English words, such as (relationships, rhinoplasties), and how to compute a “score” for such anagrams by some reasonable … Continue reading

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Array resizing in MATLAB

I encountered the following MATLAB code recently, simplified for this discussion; it builds a 3-by-4-by-2 array by assigning each of its three 4-by-2 “block” sub-arrays in turn to an initially empty array: As this example shows, MATLAB allows resizing arrays on … Continue reading

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Guess the number

I haven’t posted a puzzle in a while.  The following problem has the usual nice characteristics; it works on a cocktail napkin or as a programming problem, via exact solution or simulation, etc. I am thinking of a randomly selected … Continue reading

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Probability of a Scrabble bingo

My wife and I have been playing Scrabble recently.  She is much better at the game than I am, which seems to be the case with most games we play.  But neither of us are experts, so that bingos— playing all … Continue reading

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