Persnickety Puzzling Puzzles….

For your weekend delectation….

A recent Jason Rosenhouse post offers some thought puzzles of a certain style here:

http://scienceblogs.com/evolutionblog/2013/03/20/some-brainteasers/

(here's the style: "If you ask me on Friday what day classes start, and I truthfully reply that they start two days after the day before the day after tomorrow, then on what day do classes start?")
;-) have at it!

And in the oldie-but-goodie brain-stretching department, it probably doesn't get any better than the classic "two envelope problem/paradox" (picking/switching between 2 envelopes of differing dollar amounts; one has n dollars, the other contains 2n dollars -- after you pick one and look inside, is it more advantageous to keep the chosen one or switch to the unchosen?) -- as is often the case, the precise, explicit statement or set-up of the problem is crucial in determining a solution (but even when the set-up is agreed-upon, debate ensues!). Most of you are probably somewhat familiar with the problem, but you can review it at Wikipedia here:

http://en.wikipedia.org/wiki/Two_envelopes_problem

Keith Devlin gives his take here:

http://www.maa.org/devlin/devlin_0708_04.html

I especially like William Briggs' methodical analysis in 2 posts here:

http://wmbriggs.com/blog/?p=2645
http://wmbriggs.com/blog/?p=2649

And another interesting piece:

http://phys.org/news169811689.html

But it goes on and on and on…. a Google search produces copious material on this simple-to-state, insidiously-mind-bending problem:

http://tinyurl.com/c3ojp5v

(...don't blame me if your head explodes)