LSAT: Questions

Start out by SEALing the game. The Situation is doctoral candidates defending their theses. The Entities are A, B, C, D, E, F, G, H, and I. The Action is distribution, as we have nine candidates defending on three days, and our task is to figure out who is defending when. Limitations? 3 candidates per day.

Our sketch is pretty simple: 3 days, 3 per slots per day.

M: _ _ _ T: _ _ _ W: _ _ _

Go on to the rules.

The first rule states that B defends his thesis on Tuesday. That is concrete, and can be built directly into the sketch, giving us:

M: _ _ _ T: B _ _ W: _ _ _

The second and third rules are similar in that they dictate two pairs that must always defend their theses on the same day. This is essential. It means that wherever you place A, you must place E as well, and that wherever you C goes, F must follow. You can abbreviate these rules as ALWAYS AE, and ALWAYS CF.

The same principle applies to rules 4, 5, and 6. They tell us about entities that can NEVER be placed together. As such, whenever, you deal with G, always remember that H cannot be placed on the same day, and vice versa. The same goes for B and I and for C and I. You can put these rules in shorthand as NEVER GH, NEVER BI, and NEVER CI, respectively.

It does not seem like we have a whole lot of concrete information to work with - only one concrete rule that could be built into the sketch and no if-then rules to contrapose. But there are still a couple of really important things that we can deduce.

We know that A and E must be together, and that C and F must be together. So can A and C ever be together? No. A and C both carry along baggage (E and F, respectively), and there are only three slots per day, so A and C can never defend their theses on the same day. By the same token, A and F, E and C, and E and F are also all unacceptable.

Also, we know from the rules that C and I cannot be together. We also know that C must always be with F. Therefore, F and I can also never be together.

Update our never list - the list of pairs that can never be together:

NEVER:

G and H
B and I
C and I
F and I
A and C
A and F
E and C
E and F

Several questions hinge on these essential deductions, so if you were able to deduce them before getting into the questions that should have been a huge help. If not, you could still have gotten to the same conclusions indirectly through trial and error.

This question asks us which of the answer choices could not be (all ... except) a complete and accurate list of the candidates who defend their theses on Wednesday. This question will require a little bit of trial and error, in combination with taking advantage of previous work. We'll plug the answer choices into the sketch, build on them to see if we can get them to work.

(A) gives us C, F, and G defending their theses on Wednesday. You may have noticed that this is the same group of candidates who defended their theses on Wednesday in the correct answer to the first question. If you didn't, that's okay. You could have still used trial and error to come up with an acceptable schedule. You start out with what you know:

Mon: _ _ _ Tues: B _ _ Wed: C F G

and then see how you can fit in the other entities. One possible solution is:

Mon: A E I Tues: B D H Wed: C F G

Since we got this to work out, it is NOT the correct answer.

(B) gives us C, F, and H on Wednesday. Since G and H are interchangeable, and C, F,G was okay, this would be an acceptable schedule as well, which also makes it a wrong answer.

(C) Has A, E, and G defending their theses on Wednesday. We can get that to work out as well.

Mon: C F G Tues: B D H Wed: A E G

What about choice (D), where A, D, and E defend their theses on Wednesday?

Mon: _ _ _ Tues: B _ _ Wed: A D E

I cannot defend her thesis on Tuesday, because she cannot go on the same day as B, so let's fill her in on Monday.

Mon: I _ _ Tues: B _ _ Wed: A D E

We know from rule 6 that I and C cannot defend their theses on the same day, so C, and therefore F, must defend their theses on Tuesday

Mon: I _ _ Tues: B C F Wed: A D E

Which entities are left over? Only G and H. The only slots for them are on Monday, but according to rule 4, G and H cannot defend their theses on the same day, so this answer choice does not work, which makes it the correct answer.

Just in case you wanted to verify, choice (E) has D, H, and I on Wednesday. A possible schedule containing that arrangement is:

Mon: C F G Tues: A B E Wed: D H I