In this test four options will be shown together with a simple rule. Your job is to pick the card(s) (and only those necessary) which you must turn over in order to test if the card satisfy the rule. An example to help you on your way:
You are shown a set of four cards placed on a table, each of which has a number on one side and a colored patch on the other side. The visible faces of the cards show 3, 8, yellow and green. Which card(s) must you turn over in order to test if the cards satisfy the rule that if a card shows an even number on one face, then its opposite face is yellow?
The correct respons is to turn over the 8 and the green card.
The rule was "if the card shows an even number on one face, then its oppostie face is yellow". Only a card with both an even number on one face and something other than yellow on the other face can invalidate this rule:
- If the 3 card is yellow (or green), that does not violate the rule. The rule makes no claims about odd numbers.
- If the 8 card is not yellow, it violates the rule.
- If the yellow card is odd (or even), that does not violate the rule. The yellow color is not exclusive to even numbers.
- If the green card is even, it violates the rule.
