Q3

[christinamattos]

I am trying to work on this game and I am stumped at question 3. I set up the constraints and the board and I think I got 1 & 2 correct, but I don't know how to go about solving 3. Help is greatly appreciated!

[bbirdwell]

Hopefully you set up a number line, or at least thinking like a number line. That will help you.

Well, the obvious answer (6:00) is not a choice! We'll have to think about this. What is the most limiting constraint on the board? The chunk!!

"Chunks" are groups of 2 or 3 elements that must be ordered consecutively, and they play an important role in numbered ordering games like this one.

Here, we have the chunk WY. (It could also be YW but that doesn't matter for this particular problem.) So, rather than just thinking about U, think about how U's placement might affect the WY chunk. Typically on a question like this, there will be a place on the number line that, if U goes there, there will be no room left for the chunk.

And that spot is most likely to be near the middle, where you're more likely to break up the chunk by pushing it to one side or the other.

Note that the chunk also has to have at least one element in front of it: S.

So, if U is 1st, no big deal. Plenty of space for everyone.

If U is 2nd, no big deal. S can go first, everyone else can come later.

BUT if U is 3rd, major problems. There're two spots to the left of U and only one element (S) is qualified to go there. The chunk can't go to the left of U because there isn't enough space. And the chunk can't go to the right of U because there isn't enough space there, either.

Thus, (C) is our answer.

AND, it's important to realize that we just picked up an inference that we didn't previously have. The game just told us something we can use on all the rest of the problems: U can't go 3rd!

Is that clear?