Although I like puzzles of all kinds, my favorite type seems impossible to solve at first!
I don't know what this type of puzzle is called...I tend to call them the "Engineer, Brakeman, and Conductor" puzzles, because my very first encounter with these logic puzzles as a kid involved three employees who worked for the railroad.
If I knew what to search for, I would scour the internet for more of them! (So if you know of more puzzles like this, please send them my way.)
This particular puzzle concerns three couples out on a date. No one is sitting next to or directly opposite their date. Arran tells Nick's date that he likes her red shoes.
Who is David's date?
On the surface, there just doesn't seem to be much to go on. But the key is to start with what we know, and see if that leads to something else. Here we go!
STEP ONE: Set up a matrix
These kinds of puzzles call for some graph or chart to track our findings. The key to solving the puzzle is the process of elimination—let's see what relationships we can definitely rule out.
I like to create a matrix based on the puzzle's subjects.
STEP TWO: You can't date yourself
We know that every person at the table is dating someone, but it's impossible to date yourself. (Well, no—I believe strongly in the benefit of occasionally taking yourself out to do something enjoyable and engaging.) But in the context of this puzzle, we can eliminate each person dating himself/herself.
STEP THREE: Proximity
The puzzle tells us that no one is sitting next to or across from their date. If we start with each person and look at their seating position one at a time, we can start to rule out a number of relationships.
For example, if we start with David, we see that he's sitting next to Nick and across from Arran, so we can definitely rule out those people. (Are any of the couples same-sex? The puzzle doesn't specifically mention this, so let's assume that could be a possibility.)
Continuing on, we note that Nick is sitting next to David and Hayley, and across from Janice, so none of these people can be his date. If we work our way through the group, we're able to eliminate a number of possibilities.
STEP FOUR: The red shoes
The puzzle also tells is that "Arran tells Nick's date that he likes her red shoes." In this case, the 'red shoes' are just a distraction, because in the context of this puzzle they're a meaningless clue. But we do learn two things here:
- Arran is not Nick's date, because we know that Nick has a date
- Nick's date is a woman, so he is clearly not in a same-sex relationship.
So we can eliminate Nick as a date for Arran.
STEP FIVE: It can only be Charlotte
Once we eliminate Nick as Arran's date, we see that there is only one option for Nick's date: Charlotte.
STEP SIX: We have a match!
So now we've solved one couple—Nick and Charlotte. So now we can cancel out any of the other possibilities for Charlotte, because she's with Nick,
STEP SEVEN: We have another match!
When we X out Charlotte's other possibilities, we see now that Arran only has one remaining possibility—Heyley.
STEP EIGHT: The only ones left
Now that we know the second couple is Arran and Heyley, it's clear that the only ones left are Janice and David.
STEP NINE: We have a solution!
So David and Janice are together, so we now have a solution to the original question: Who is David's date? We can confidently answer Janice.
How did you do?
