Three prisoners, A, B, C are in their cells. They are told that one of them will be executed the next day and the others will be pardoned. Only the governor knows who will be executed. Prisoner A asks the guard a favor. “Please ask the governor who will be executed, and then tell either prisoner B or C that they will be pardoned.” The guard does as was asked and then comes back and tells prisoner A that he has told prisoner B that he (B) will be pardoned. What are prisoner A’s chances of being executed, given this message? Is there more information than before his request to the guard? (Adapted from Pearl 1988).