Thanks for the question! This is definitely a tough game, so let’s walk through why (B) is correct and why (E) is incorrect.
Now, this is a must be true question, which means that we should be able to solve it based off our diagram alone. We do have to chain together a number of things to get there, but we can get there eventually.
First, note that J evaluates X (an advanced book) during week 4 based on the last rule. Now, recall that J has to evaluate advanced books after R evaluates them, which means that R evaluated X sometime between weeks 1 and 3.
Now, can R have evaluated X in slot 2? Well, what could R have evaluated in slot 1? The answer is: not an intro book. R has to have evaluated an advanced book in slot 1. Why? Because R can’t evaluate any introductory books until J sees them, so the first book that R evaluates has to be advanced. But if R evaluates two advanced books in a row, R also have to evaluate two introductory books in a row at some point (because there’s three of each and six total slots).
The X talk is kind of perpendicular, but helps you narrow down the placement of X. Obviously, you could have done this as well by just noting that R can’t evaluate an introductory book first, and can never evaluate two in a row, so R has to go AIAIAI. What does that mean? R has to evaluate an advanced textbook during week 3, which is what (B) tells us, and so (B) is the correct answer.
(E), on the other hand, doesn’t necessarily have to be true. While we know that R can’t evaluate any two introductory textbooks consecutively, it’s completely possible for J to do so, and if you work through a couple of hypotheticals, you can definitely come up with something where J evaluates two introductory textbooks in a row. So (E) is wrong.
Hope this helps! Feel free to ask any other questions that you might have.
ChrisOctober 11, 2023
So can you work through some hypotheticals where J can evaluate two I's consecutively? I am not able to come up with one.
Emil-KunkinOctober 13, 2023
I think we could have the following:
J: F G Y X H Z R: Y F X G Z H
It looks kosher to have two intros to start for j.
