LSAT PrepTest 20 Section 4 Question 3 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 October 1996 LSAT.

The argument: these trucks have fewer accidents per mile than other commercial vehicles, so they're safer. Many different things might weaken this argument; if you can think of something, maybe look for it, but if not, don't worry. We'll just jump into the choices:

A) The opposite of what we want since this strengthens the argument; other commercial vehicles not only get into more accidents, but also carry less, so more vehicles would be needed. So, the crashes per mile would be even more high than triple trailers.

B) Correct. These statistics are about the averages in Western states and the argument compares them to the national averages...if the Western states have safer highways, then it's likely there will be fewer accidents from the triple trailers that travel there even though those trucks may not be any safer than commercial vehicles in general.

C) Out of scope. What the opponents previously opposed doesn't prove anything about if triple trailers are safer than other commercial vehicles.

D) Out of scope since, as a reader astutely pointed out below, we don't know if those special requirements are more stringent or not. They may not have any effect on the quality of driver that drives triple trailers and, if that's the case, there's no reason to think the requirements would affect the number of accidents. So, the requirements don't really have much to do with the argument.

E) Out of scope again. Maybe, despite this increase, it's still a lower rate of accidents than commercial vehicles and the triple trailers are safer. The argument doesn't address the current trend in the trailers; it says only that they have less accidents than other vehicles.

Remember:

Watch out for choices that are out of scope (if the argument doesn't talk about what the choice does, the choice doesn't weaken the argument since it doesn't even address the argument) or are the opposite (in this case, strengthen the argument; this is pretty common n the LSAT arguments) of what we're looking for.