4 ms·

>If a card shows an even number on one side, then its opposite side is blue. As the problem fails to specify that the card has a number on one side and a color

• mpeg 3y ago
  No, you don't. You still only have to check those 2 cards. If you're asking about card 3 then that's the common mistake – it doesn't matter whether that card has a number or an emoji on the other side, because the only logical test here is that if it has an even number on one side, the other side must be blue. It doesn't matter what blue cards have on the other side, we don't need to test them. edit: sorry, I just realised you're referring to card 1 and not 3, yeah I suppose you'd need to check it too unless there's a rule about always needing to match a color to a number.
  • quirino 3y ago
    What they mean is that the card that has a 3 on the front might have an even number on the back.
    • mpeg 3y ago
      yep I just realised and edited my comment, I imagine the full question has a clearer description that OP cut down for the blog post.
      • mlajtos 3y ago
        To be fair and square, I added an explicit statement about consistency of the cards, so it is clear.