Submitted by david on Mon, 31/10/2011 - 8:49am
I recently tweeted a link to this problem drawn on a blackboard, which got a lot of retweets.
Multiple Choice: If you choose an answer to this question at random, what is the chance you will be correct? A) 25% B) 50% C) 60% D) 25%
This is a fun question whose paradoxical, self-referential nature quickly reveals itself – A) seems to be fine until one realizes the D) option is also 25%.