Category Archives: puzzles

A reasoning puzzle– *the* answer

by Greg Mayer So, here’s the answer given by Manil Suri to the puzzle he posed in the New York Times on Sunday. First, restating the puzzle: Four cards are laid in front of you, each of which, it is explained, has a letter on one side and a number on the other. The sides […]

A reasoning puzzle– an answer

by Greg Mayer Reader Chris G. sent a video of Steve Pinker explaining the very same problem (another reader also mentioned that he had seen a Pinker talk about it). Here it is. I’ll post my own discussion later today. h/t Chris G.

A reasoning puzzle

by Greg Mayer In today’s New York Times, there is an opinion piece by Manil Suri, a mathematician at the University of Maryland, Baltimore County, entitled “Does math make you smarter?” Don’t go and read the piece– that’s why I’ve left out the link! I ask that readers answer the following puzzle he poses in […]

Bertrand’s Box paradox: The answer is 2/3!!!

There are almost 200 comments now on my post about Bertrand’s Box Paradox yesterday. Let me reprise the problem and then give the solution the way I hit on it: There are three boxes: a box containing two gold coins, a box containing two silver coins, a box containing one gold coin and a silver […]

Bertrand’s paradox

Reader Peter sent me this paradox (it’s not really a “paradox” as I understand the meaning of that term, but a result that, like the Monty Hall problem, is deeply counterintuitive). It’s called Bertrand’s Box Paradox after French mathematician Joseph Bertrand, who raised it in an 1889 book on probabilities. The setup is simple: There […]

A biological puzzle

This was called to my attention by reader Douglas Swartzenruber, who put it on his website, “A View from Planet Boulder”.  (Do not click the link yet). First, there are these “moguls” made by skiers; Douglas explains: For any non-skiers out there, moguls are formed on steeper slopes when numerous skiers follow the same route […]

Snow puzzle

UPDATE: I’ve put Christopher’s response below in the comments; it’s #20. Reader Christopher Moss sent this snow conundrum, and I’ll supply the answer in the comments at 11 a.m. Chicago time. Here’s the picture and the query, whose answer of course involves an animal. My front deck with two inches of fluffy snow that fell […]

Robot solves Rubik’s cube in one second

Here’s a robot solving a Rubik’s cube in a tad over one second. It’s not an official record for a machine yet (that’s 2.39 seconds), but they’ll get the Guinness record before too long. Gizmag gives more information about how the robot works, and I’ll let the geekier readers read the details there. There’s an […]