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 Paul Marsh
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Hi medialaw!

When you see "only if" in the stimulus of a Parallel or Parallel Flaw question, don't think that the correct answer choice will also definitely need to use the words "only if". It doesn't. The important thing to note about "only if" for Parallel questions is that it always introduces the necessary condition of a conditional. So if it appears in a sentence in the stimulus, then the corresponding sentence in the correct answer choice must also have language that introduces the necessary condition. For example, look at these two sentences that I'll call A) and B).

A) If I am happy, then that means I just pet a dog.

B) I am happy only if I just pet a dog

Both A and B are identical, as they represent the following conditional:

Happy :arrow: Just pet a dog

So if my sentence A) appeared as a premise in the stimulus of a Parallel question, and B) appeared in the answer choice, that would be totally fine.

(As an aside, If "only if", or conditional logic in general, is proving difficult for you, don't feel bad. Conditional logic is a very difficult topic for many people studying the LSAT. Unfortunately, a solid understanding of the topic is required for someone hoping for a very good LSAT score. Review Lesson 2 from the Course Books and all the homework at the back of that lesson. If you still need more practice, a session or two with a PowerScore private tutor might not be a bad idea. Or if you're in college and have some time before you take the LSAT, consider signing up for an Intro to Logic class, where you'll learn all this stuff in great deal.)

Now in this question, the first sentence of the stimulus can be broken down into conditional logic as follows:

A student who wants to participate is eligible :arrow: At least one archaeology course + Interest in the field

The first sentence of answer choice (B) nicely mirrors that conditional logic (even though it doesn't use the words "only if"):

Well schooled horse is ideal for beginners :arrow: Surefooted + Gentle

This question is a bit tricky. For most Parallel Flaw questions that use conditional reasoning, the Flaw ends up being an incorrect use of necessary and sufficient conditions (e.g. a Mistaken Reversal). Here, that's not the case. Instead, the Flaw is that the second premise of the stimulus tells us about students who are interested in archaeology, while the conclusion switches things on us and starts talking about students who are interested in the dig. Those two groups are not the same! For all we know, everybody interested in the dig has taken an archaeology course, and is interested in the field. So the conclusion is not supported by the premises. We are looking for an answer choice that similarly switches things up on us between second premise and conclusion, and answer choice (B) fits the bill. Hope that helps!
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I understand why D is not correct for this particular question but I am unsure as to why the argument is nonsensical. Is it because new automobiles may not be maintained? How would I diagram this?

Thank you in advance!
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Hi lmasta0340!

Here's how I would diagram answer choice (D):

1st sentence:

regularly maintained :arrow: eventually need repairs

2nd & 3rd sentence:

currently need repairs :arrow: regularly maintained

As illustrated by the diagram, this argument does not make sense because the conclusion does not follow from the conditional relationship set up by the first sentence. The first sentence just tells us that older autos that aren't regularly maintained will EVENTUALLY need repairs. Just because there are older autos that don't currently need repairs doesn't mean that they won't EVENTUALLY need repairs. Their current repair needs are not enough to confirm that they are regularly maintained.

Hope this helps!

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Thank you both!

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