SPEAKER 1: So let's take a look at the puzzle logic gate.
In this puzzle, you're presented with a grid and a set of rules.
And basically your objective in this puzzle
is to figure out which student is of which year
and which student is seated at which terminal.
And you can actually figure this all this information out just
from these four sentences here, and then there's
one more step that we'll get to at the very end of the puzzle.
But our goal is to figure out who is what basically.
So let's start looking at the first clue.
The student sitting at terminal number eight
has been in college longer than Charlie.
What does this tell us?
Well, it's actually tells us a couple of things.
First, we know that Charlie is not seated at terminal eight,
because they are two--
we're talking about two different people.
So we can basically X that one out or color it in red
or whatever we want to do on our grid.
The other thing we know is that the student sitting at terminal eight
cannot be a freshmen, because they've been in college longer than Charlie.
So we can also X that one out.
And similarly, do we know that Charlie cannot be a senior,
because if they have been in college longer than Charlie,
Charlie can be the oldest one of the group.
So we can X all of those out.
Now let's look at the second clue.
This one's a little more straightforward.
It says Diane is a freshman.
Well that actually gives us a lot of information.
We can actually color in blue or green or check
mark or whatever you want to do to mark this on your grid
that Diane is a freshmen.
And it also tells us a little bit more.
It also tells us that none of the other three remaining students
can possibly be freshmen, and it also tells us that Diane can't possibly
be a sophomore, junior, or senior.
So we can actually out all of those as well.
The third clue is very similar.
Charlie is sitting at terminal nine.
So just like we did with Diane being a freshman,
we can similarly fill in Charlie as at terminal nine
and cross out all of the other possibilities for terminal nine
and for Charlie.
And then we have our fourth clue here.
Alice is one year behind the student sitting at terminal number 10.
So much like the first clue, we actually get three pieces
of information out of this directly.
The first is that, of course, Alice is not the student seated
at terminal 10 for the same reason.
We're talking about two different people here.
The next is that it also means that the person who is seated at Terminal 10
cannot be a freshmen because Alice is one year behind them.
And it also means that Alice cannot be a senior,
because she is one year behind the students at terminal 10.
But what does this also tell us?
You'll notice that if I go back to the previous slide for a second,
there's only one possibility left now for a senior
if we look at that top left, sort of, larger square,
and that must mean that Bob has to be a senior.
We've excluded every other possibility for who could be a senior,
and Bob cannot be any other year.
So now we have a couple of conclusions that we
can draw from what we have left.
And let's start by looking at who could be seated at terminal number 10.
Let's take a look at that fourth clue again.
There are only two options left if we look right here and right here.
And the only two options left are Bob and Diane.
But now we have to, sort of, synthesize the clues we've already had.
It can't be Diane, because Diane we know already is a freshmen
and we know that Alice is younger than the person who
is seated at terminal number 10.
So if Diane was seated there, Alice couldn't be younger than her.
And so Bob has to be the person who is seated at terminal number 10.
Now in addition, because we know that Alice
is one year younger than the person seated at terminal number 10,
that means that Alice has to be a junior, because Bob is a senior
and Bob is seated at terminal number 10.
And that only leaves one option left for Charlie
there in that square on the top left, which is that he must be a sophomore.
And then finally, we know that the student who
is seated at terminal number eight has been in college longer than Charlie
and we know now that Charlie is a sophomore.
And among Diane and Alice who are the last two left
to figure out in that top right square, that's only true of Alice.
Alice is the only one who's been there longer than Charlie of those two,
so she has to be seen at terminal number eight
and Diane must be at terminal number 11.
And now we, kind of, filled out everybody's information,
so we can also fill in everything in that bottom grid as well based on all
the information that we already have.
Now for that last piece of the puzzle here, originally, as you know,
all of those squares that we just filled in had letters in them.
And if we just focus on the ones now that reflect
all of the true relationships in this puzzle,
we see these are the letters left.
And if we read them from left to right, top to bottom,
we're left with the word architecture, and that was the answer to this puzzle.