Statement: If a card has a vowel on one side, then it has an even number on the other side.
First of all, we need to understand that the statement means the following:
1. Every card with a vowel on one side will have an even number on the other side.
2. A card which doesn't have an even number on one side cannot have a vowel on another side. (since if it had had a vowel on another side, it would have had an even number on the initial side)
3. No information is given about cards which don't have vowels on one side. They may have even numbers or odd numbers on the other side. (Assuming that each card has an alphabet on one side and an integer on another side.)
4. Based on points 1 and 3 above, we can say that a card with an even number on one side can have a vowel or a consonant on another side.
Thus, we can say that the statement doesn't make any conclusive statement about cards which have either a consonant or an even number on one side.
Thus, we'll not be able to verify the statement by flipping over X or 8.
However, the statement makes conclusive statements about cards which have either a vowel (must have an even number on another side) or an odd number on one side (cannot have a vowel on another side).
Thus, flipping over the card with A and the card with 3 will help us verify the truth value of the statement.
If we don't make the assumption made in point 3 above, flipping over the card with 'X' would also be helpful since per the statement, it cannot have a vowel on another side.
Hope it helps!
- CJ
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