LSAT PrepTest 42 Section 1 Question 5 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 another Logic Games question from the December 2003 LSAT.

Let's re-use a diagram from the last question:

FGHLP

This fits the situation in the question (GH are selected), and C is out now (neither K nor M is in the diagram), as is D (neither M nor Q are in it). If neither one's in this correct diagram, that choice can't be right.

So we're down to A, B, and E. Let's try to violate the first choice by making a diagram without F or K. We’ll pick GH. We have to get 2 chemists, since we can pick only 1 zoologist (according to the rules), and we need 5 scientists in total. So we have GH, and we try to select L and M, but we can’t. Why? Because selecting M means taking P and R, which we can’t do. Therefore, we can't get by without taking one of F or K, and we know A is correct.

Remember:

Re-use old diagrams whenever possible and violate as many choices as possible when you make a new diagram; if you definitely cannot violate a choice, as was the case here, it means the choice has to be correct.