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?

(In reply to Solution by Penny)

If the hypothesis had been "The number is 4 if and only if the letter is E", then all four cards would have to be turned over.

 

 

 

 

Edited on December 15, 2004, 3:40 pm

Posted by Penny on 2004-12-15 15:40:00