June 2007 LSAT, Game 2, #7

Let's continue through Game 2 of the June 2007 LSAT.  Yesterday, I created a setup for the game and answered the first question. I answered #6 pretty confidently, but didn't make all that many inferences in the setup. So I'm still a bit apprehensive--have I missed something? Maybe Question 7 will help me find out. The question says "Which one of the following CANNOT be true?" There's no new information here, so I can't build a new diagram for this question. Instead, I'll just have to evaluate the answer choices. In doing so, I'll be relying on my main setup, which looked like this:

Thursday:                                                            H   |

Friday:                                                             G/L    | (not both G&L)

Saturday:                                                         G/H   | (not both G&H)

Since this is a "must be" question (must be false), it should be easier to positively identify the CORRECT answer than to eliminate the incorrect answers. (Contrast this approach with the process of elimination I used on the "could be true" question #6.)

On #7, if there is one (correct) answer that must be false, then there are four (incorrect) answers that could be true. The key is to not spend too much time proving that the incorrect answers are actually possible. I"ll just say "I don't see why not," and move on. Ideally, the correct answer is going to jump out at me and say "I'm a problem!" I need to move fairly quickly through all five answers in the hopes that the right answer will jump out at me.

A)  Well, that was easy. H must be shown last on Thursday, and can be shown last on Saturday. But Rule 2 said that either G or L has to be shown last on Friday. Based on that one rule alone, Answer A must be false. So this will turn out to be our answer. Just to be sure, I'll scan through B-E and make sure none of them look problematic.

B)  Sure, why not? The only potential problem here is if L is shown on Friday then G can't be shown on Friday... but there's no reason why G has to be shown on Friday. So this is possible, and that means it's not our answer.

C)  Sure, why not? If Thursday was L, G, H, then G would be second that day. If Friday was H, G then G would be second that day. If Saturday was L, G then G would be second that day. No problem, so this is out.

D)  Many ways to do this. No big deal, so this is out.

E)  H on Thursday, G on Friday, L on Saturday is the only way to do this. But it works, so this is out. Our answer is certainly A.

At this point, you might be asking whether I really needed to go through B-E here, having positively identified A as the correct answer. I definitely understand your point. but I've learned, through long practice on the LSAT Logic Games, that cutting corners is really not the best strategy. Going through B-E took me about 20 seconds total, and allowed me to answer the question with 100% certainty. I have learned that attempting to save 20 seconds can sometimes cost 5 minutes. On later questions (more difficult questions) you might see me take a calculated risk here and there. But on this one, since it's still early in the game, I wanted to make sure that none of the other answers seemed correct. Having narrowed it down to one and only one answer, I'll proceed through the rest of the questions on this game with a bit more certainty. Thanks for reading!