LSAT PrepTest 43 Section 2 Question 11 Explanation | Logical Reasoning

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 Logical Reasoning question from the June 2004 LSAT.

This is pretty straightforward, so I don't think we need to make a big deal out of having a chain of phrases here. QI's system is cheap enough, and Corelink's is cheaper, so Corelink's must be cheap enough; this is the essential claim. Let's pre-phrase the idea here, so we can look for this underlying idea in the answer choices. It's something like "one thing meets a standard, and another thing is even better, so it meets the standard too." In this case, the standard was being cheap, but it might be anything. Now, let's go through the choices:

A) Out of scope because height doesn't necessarily mean that one has meet or exceeded the standard here (being able to touch the ceiling). Maybe John's taller than her but weighs 400 pounds and can't jump over a phone book! This choice doesn't conform to the underlying idea.

B) Wrong for the same reason as B. Just because one smokes less than the other doesn't mean she can run as far.

C) The opposite of what we want because, unlike the logically sound underlying idea of this argument, this conclusion clearly doesn't follow. If the legal limit is 0.10 and John had a 0.20, maybe Paul had a 0.05, which would be below John and legal. Just because John's is high doesn't mean Paul's lower level is illegal.

D) Out of scope because the argument's idea involves drawing a conclusion from the fact that something met or exceeded a standard. Here, the conclusion's based on the chocolate not meeting the standard, which isn't the same pattern of reasoning as the argument.

E) Correct. One cheese meets the standard, and another is even better, so it must meet the standard of being low-fat too. This parallels the argument exactly.

Remember:

1) Pre-phrase even a basic, underlying idea, if you think it will help. On parallel-reasoning questions like this one, I think it's a good idea to pre-phrase what the kind of reasoning we're looking for is.

2) Ditch choices that are out of scope (in this case, talk about things unrelated to the kind of reasoning we're looking for) or the opposite of what we want (choices whose logic is entirely wrong, and thus doesn't parallel the argument at all).