04.02.08
Testing
Let’s say there are 4 index cards in front of you. Each one has a letter written on one side and a number on the other. The ones that you see have the following written on the visible sides:
[ A ] [ D ] [ 4 ] [ 7 ]
Then, you are told the following rule: If a card has a vowel on one side, there must be an even number on the other side.
1) What is the minimum number of cards that you have to turn over to determine if this rule is true?
2) Which card(s) do you have to check to ascertain if the rule is true?
Answers under the fold.
1) 2 cards
2) Card [ A ] and Card [ 7 ]