I present to you a deck of 4 cards. Each card has on one side a letter of the alphabet, and on the other side a single digit from 0-9.

I propose a hypothesis that may apply to this deck:
If the letter is 'E', then the number on the other side is '4'.

I then drop the 4 cards on the table, and you see: 'B', '7', 'E', '4' (on the respective cards).

Which of the 4 cards must you turn over to verify or disprove my hypothesis?

I really like this problem, since it shows that a fairly easy logical question can confuse smart people. Although OOO (and others) got the right answer, several other possibilities were posted that "seemed" to make sense. Definitely shows the value of using formal methods to answer logic questions.

Posted by SteveH on 2004-12-15 17:18:28