You would need to turn over two cards - A and 3. A is a vowel so we need to confirm the rule. K is not a vowel so we ignore this card. 3 is not an even number so we need to make sure that there is no vowel on the other side in order to confirm our rule. 8 is an even number but we can ignore this card because the rule only states that an even number needs to be present if a vowel is on the card but not the other way around. A and 3 are our cards :)