bits and pieces

logic puzzles

logic puzzles can be fun, if you enjoy working on tiny bits of info and focusing on details that ultimately have no bearing on your life (I like them because they make me focus on not-life really intensively).

I think you really need to be eased in to them in order to understand or possibly enjoy them, though. I really like Penny/Dell Logic Puzzle magazines, which usualy show up on the bottom shelp of magazine racks hidden behind sudoku and crosswords. If you find yourself in a situation where you need to "practice logic" (do the work a computer should be doing for you), I would recommend getting one of those and doing several a day. Logic variety packs are also pretty sweet.

A Definitely-not-beginner-level question:

An camp counselor must assign cabins to this season's campers. Seven different cabins are in a row leading away from the community hut, and are numbered one through seven, with cabin 1 being closest to the community hut and cabin 7 being furthest away. Seven different campers - Billy, Chasey, Dan, Felicia, Harold, Jamal, and Kindra - are this season's guests. Only one camper can be assigned to each cabin. The assignment of the cabins is subject to the following restrictions:

Billy and Dan must be in consecutive cabins.

Billy needs to be closer to the community hut than Kindra.

Dan must be further from the community hut than Harold.

If Harold doesn't get cabin 4, then Felicia gets cabin 4.

Kindra and and Jamal cannot be in cabins that are side-by-side.

PART 1: so the part about the camp counselor and the cabins? That's just a distraction. You should read it, because sometimes puzzle writers like to hide clues in that part, but 9 times out of 10, it's just fluff to give the story a veneer of reality. In Puzzle Books, it's usually when the puzzle writer gets her or his terrible pun squeezed in. In tests, it's probably to add legitimacy to the test question. :P

You are going to want a couple sheets of paper for this. You'll probably find a pencil better than a pen, but whatever.

PART 2: Computer languages set up logic/syntax so that yu can type in short hand for all the relationships that the campers have. For instance, `If spot4 !='Harold', THEN spot4 ='Felicia'` conveys that if spot 4 is not Harold, then it is Felicia. You are going to want to have some form of notation that you can remember, and most logic puzzles have the decency to give each camper (or whatever variable the puzzle is about) a name that starts with a different letter-- I'll be referring to campers by letters only from here on out. I like to use dots or short dashes to show that 2 things are next to each other, double dashes to show that one object is some unspecified amount of space before another, and an 'x-` to say 2 things are not next to each other.

Be careful with logic puzzles, because they will use slippery words like "consecutive" or flip "comes before" and "comes after" one right after the other. Pay very close attention to these "clue" sentences and be sure to make notes that are in the same format.

For instance, B comes before K would make a note like B--K, but D comes after H would make a note like H--D, because mentally, we want to sort these the same way, and that sentence means the same as H comes before D.

Remember that consecutive just means one-after-the-other, so B could be immediately before OR immediately after D. I normally note this like so: B-D-B

ALWAYS feel free to tweek these styles to fit your preferences, or if the logic puzzle doesn't work with the usual way you solve problems, just be sure that you are consistent within an individual puzzle.

PART 3: Now that you have notes, look for relationships between the clues- like, is a letter mentioned in more than one clue?

so: what questions have B in them? We see that b is conseutive to d and also before k. I would note that b-d-b--k, but you could write it any way that makes sense to you (like b/d-?-k for instance)

d is consecutive to b and h must come before it. That part would be h--b-d-b (or h-?-b/d). Smooshing both of those together would give h--b-d-b--k

At this point, I notice that h might be in the 4th spot. if it was, then b,d, and k would have to appear in spots 5, 6, and 7. But, in the case when h is not in the 4th spot (and f ish), then all bets are off.

Holy socks, Batman, that's a lot of work and we haven't even gotten to the first question yet! That's ok. These early parts are important, so that you don't get tripped up later. Most of the questions are just going to be "can you plug it in this way?" and by putting together lovely long sets like h--b-d-b--k will help you eliminate things quickly.

1.Which of the following could be a possible cabin order for the campers to be assigned?

(A) BDFHJCK

(B) CJBHDKF

(C) HBDFJCK

(D) HDBFKJC

(E) HJDBFKC

Only keeping h--b-d-b--k in mind, we can look at the answers and say

• There's no room for h at the begining, so it can't be A)
• b and d anren't next to each other, so it can't be B)
• C) could be it
• D) could be it
• E) could be it

Awesome! What next in our notes? h or f must be in cabin 4...

• f is there, so C) is still good
• f's in that one, too, so D) is still good
• b... nope! We can strike E) off the possible answers list

What else is in our notes?... k and j cannot be next to each other...

• C) looks ok...
• D) -- Nope! k and j are side by side

now you'll notice that in that last section I evaluated both possible answers, even though I knew the first one was right and that there could only be one right answer (given the nature of the test-- but watch your assumptions!). This is because logic puzzles are tricksy beasts and you must always be on guard. There have been so many times when I have gone through a logic puzzle and ended up with 2 or zero right answers-- usually because some words somewhere played a trick on me early on. Go through every answer to make sure you aren't ruining logic Christmas because you misread.

Recap:

1. Distill the essence of the intro paragraph
2. Notate the intro "facts" in a consistent and clear-to-you way
3. Look for relationships between the intro facts & notate those as well
4. Carefully read the follow up question
5. Go through each option and evaluate if it could be an answer to the question or not-- strike out any that don't work
6. Even if you find an answer that fits, go through all of them, just to be sure you aren't getting tripped up by a misunderstanding (feel free to skip this if you feel confident but time constrained).