LSAT 79, Logic Game 3, Question 14

On can’t be true questions, you should look through the answers, and decide whether they make it easier to follow the rules, or harder to follow the rules.

For instance, take A. This answer places V and R together (and no one else). Which rules mention V or R? Rule 3 says that V and Y can’t go together. Since A didn’t do that, it obeys rule three, and therefore makes it easier to follow the rules.

This doesn’t prove A is possible, but it should make you suspect that it is. You should move through the answers and look for easy/hard, and then try the answers which make things hard, first.

(The way to definitively prove A would be to draw a full scenario. But that takes more time. This “easy/hard” method is intended merely to narrow down the answers to the most likely.)

• B: hard. Takes Z out of the YZ pairing. So this means we can’t place Y in P. (Effectively, B forces something to happen to a variable not mentioned in B)
• C: Easy. Places TS together, fulfilling rule 2.
• D: Easy. Places V not with Y, therefore avoids violating rule 3. (Note that this is a harder answer than B, since it does split up YZ. So Z can’t go in P.)
• E: Easy. Keeps YZ together. Since they’re both accounted for, we have avoided putting only one of them in P.

I would do B first, and then D if B isn’t right. Hopefully this method makes sense. You do a quick skim to identify which answers are most plausible, and then you try drawing only those answers.

Here’s what we can draw for B. Once we put RZ in L, that forces Y to go to M. (Rule 3: If Z isn’t in P, then Y can’t be there either):

Next hardest the place is TS, since they take two spaces. These go in P:

That leaves V to place. This doesn’t work, because YV can’t be together. And we need to place everyone. So, B is CORRECT. Every other answer works. And since we judged them all as “easy”, it wouldn’t be necessary to draw the rest in timed conditions. If I had another answer I considered “hard” to do, I would draw it as an error check. But for the rest, simply making the judgment of “easy” is the error check.

 

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