LSAT PrepTest 42 Section 1 Question 15 Explanation | Logic Games

I didn't write the following blog post. It was already on the blog when I took over the URL. The following blog post may contain mistakes. -Steve

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Here's a Logic Games question from December 2003

Let's re-use the two diagrams from the other time we worked on this game:

Monday: O, S
Tuesday: O, PB
Wednesday:
Thursday: O, PB, S
Friday: PB, S

Monday: O
Tuesday: O, PB, S
Wednesday:
Thursday: O, PB, S
Friday: PB, S

Both of the diagrams we previously made apply to this question. Let's eliminate choices based on them. Remember, since the question says, "each of the following could be true EXCEPT," we want to find the one that cannot be true.

A) Eliminated by the 1st diagram because it contains 2 kinds of cookies starting on Monday. If it happened in our correct diagram, it's possible, so we can eliminate it (since we're looking for something that isn't possible).

B) Eliminated by the 2nd diagram (PB and S).

C) Correct. This is the only one that doesn't appear in the 2 diagrams. By the process of elimination, we know all the others are possible, so this is the one choice that isn't possible, and thus the correct answer.

D) Eliminated by the 2nd diagram (again, PB and S).

E) Eliminated by both diagrams.

Remember to re-use old diagrams whenever possible to save time and increase accuracy (fewer diagrams = finishing games more quickly).