Take the test below to find out!
Here is a puzzle for you to find out.
You have been given four double-sided cards, each with a number on one side and a letter on the other. The cards, as laid out on the table are:
- E
- K
- 2
- 3
You are given the task to test this hypotheses:
“If a card has a vowel on one side, it has an even number on the other side.”
Which do you turn to prove?
If you get the answers wrong, then you need to read the book below 👇. Scroll to the bottom to find out the answer.
Answer
If your answer is E and 2, then you really need to read the book above 👆. The answer is wrong because:
- If the other side of E is an even number, it proves the positive. But what about the negative? That is, is there other instances where if you have a vowel on one side but an odd number on the other side? To do this, you need to turn over “3” to find out. To prove the hypotheses, you need to prove both the positive and negative.
- If the other side of 2 is not a vowel, that still doesn’t prove the hypotheses false. The hypotheses stated that a vowel on one side must have an even number on the other side. It does not define what the other side of a non-vowel should be. It doesn’t matter what the other side of the non-vowel is because the hypotheses does not define what it should be. So, if the other side of 2 is a non-vowel, it still does not prove the hypotheses false.
Therefore, the correct answer is E and 3. It proves both the positive and the negative. Only by proving both the positive and negative can you prove whether the entire hypotheses is true or not.