I can't make sense of "Unaligned Pair clues"

[SHolmes82]

Hi everyone,

I've decided after many years of just assuming "I can't do them", to start having a go at logic puzzles. But something I'm really struggling with is these so-called "Unaligned Pair Clues". I CANNOT get my head round them. Here's an example from the tutorials on the site:

puzzle.png


The clue here says "Of Laura and the person who got the blue tattoo, one paid $45 and the other chose the Gemini symbol." The tutorial then says that we can deduce that "Laura's tattoo isn't blue". I understand this, because I can read that "Laura" is ONE person, and "the person who got the blue tattoo" is A DIFFERENT PERSON.

What I DON'T understand is where the tutorial says that we can deduce that "The Gemini tattoo didn't cost $45". WHY??? How do we KNOW this?? Here's how the logic goes in my head:

1. Laura is one person
2. The person who got the blue tattoo is another person
3. Laura's tattoo isn't blue
4. We don't know WHICH of the two people above (Laura and the person who got the blue tattoo) paid $45, nor do we know which of the two got the Gemini tattoo.

What am I missing? Could someone PLEASE explain it to me in simple terms, because right now I feel like an idiot!

[SHolmes82]

Never mind, I think I've figured it out....

[boxeeboxeebox]

I think you got tripped up because in many manually created logic puzzles, you can't assume that all identities mentioned in clues are exclusive. For this site, because they're automatically generated, you'll only run into a few different types of clues that involve multiple possibilities:

• A is either B or C (B is not C)
• A is neither B nor C (B is not C)
• Of A & B, one is C and the other is D (A is not B, C is not D)
• A, B, C, and D are all different (A is not any of B, C, or D; B is not C or D; C is not D)

If you find that you enjoy the puzzles, I recommend picking up the books. There are some fun puzzles out there (my favourite type is where the clues contain lies).

[kgf]

As it seems you already figured out, in those kinds of clues, the two pairs will always contain mutually exclusive entities. You got "Laura" is not the "person with the blue tattoo". The other pair is the same logic - one person got a Gemini, and another paid $45, therefore the Gemini can't be $45. Where these clues come in real handy is when you have two of these clues and each contains one of the same entities. For example, if you had another clue that referred to Laura, you can then use the two clues against each other. Say the other clue is "of Laura and person with the orange tattoo, one is an Aries and the other's tattoo was done by Chuck." Using these two clues together, suppose that Laura is the Aries, then in the other clue she can't be the Gemini, therefore she would have to be the $45, so then check to see if Aries can be $45. If it can't, you know Laura can't be the Aries, and must be done by Chuck.

[evessal]

I had problems with these too. It definitely gets getting used to; most of the easy puzzles just contain all possibilities in the clue itself, but with these types of clues you can deduce other information as long as other options not mentioned in the clue belong to the same category of said options.