Release Message:  Warden tells A that B is to be executed Prisoner A believes his probability of surviving has gone up from 1/3 to 1/2. Prisoner A tells C the news, who reasons that A has a 1/3 chance to be pardoned, but C's chance has gone up to 2/3. What is the correct answer? Authored by Martin Gardner.

Description:  The Three Prisoners problem appeared in Martin Gardner's "Mathematical Games" column in Scientific American in 1959. It is mathematically equivalent to the Monty Hall problem with car and goat replaced with freedom and execution respectively, and also equivalent to, and presumably based on, Bertrand's box paradox.