PrepTest 103

[lcid:3508] Prep Test 103 LSAT — Logical Reasoning — S1 Logical reasoning

Question prompt

Not all tenured faculty Remaining source text redacted.
Why the credited answer is right

Credited answer: C

The notes below walk through why it fits the stem and how to eliminate the rest.

Argument or Facts

Argument

Valid or Flawed

Flawed

Question Type

Flawed Parallel Reasoning Questions

Stimulus Summary

Tenure --some-- ~Full professor Linguistics faculty → Tenure Therefore - Linguistics faculty --some-- ~Full professor

Answer Anticipation

A Flawed Parallel Reasoning question with quantifiers and conditionals? Gotta love it - we can diagram it out and find the correct answer quickly...as long as the flaw is related to the conditional/quantified logic. Let’s work through our diagram. First, “Not all As are B” is the same as saying, “Some As are not B,” which leads to our first premise and the conclusion. And the “although” in the conclusion is a premise - not a part of the conclusion - which is why we broke it out as we did. With that noted, we can see that the argument tries to chain a conditional into a some statement, which we can’t do. The sufficient condition of the conditional needs to be shared with the some statement for an inference to be possible, so this argument is flawed because of the conditional/quantifier logic. Let’s find an answer that follows the same pattern: A --some-- B C → A Therefore - C --some-- B

Answer choices

  1. A
    Although all modern office Remaining source text redacted.
    Why choice A is not credited
    This answer has the same quantifiers and conditionals as the stimulus, so we need to dive into the diagram:

    Modern office tower → Climate-controlled

    Office building --some-- ~Climate controlled

    We can stop here. To get the shared term to overlap, we would take the contrapositive of the conditional, and then the sufficient condition of it would be shared - so there is a valid inference to be made, unlike in the stimulus.
  2. B
    All municipal hospital buildings Remaining source text redacted.
    Why choice B is not credited
    This answer has the same quantifiers and conditionals as the stimulus, so we need to dive into the diagram:

    Municipal hospital → Massive

    Municipal hospital --some-- ...and we can hop out, as the sufficient condition of the conditional is shared, so there’s a valid inference to be made here, unlike in the stimulus.
  3. C
    Although some buildings designed Remaining source text redacted.
    Why choice C matches the stem
    This answer has the same quantifiers and conditionals as the stimulus, so we need to dive into the diagram:

    Designed by famous architect --some-- ~Well proportioned

    Government building → Designed by famous architect

    Therefore - Government building --some-- ~Well proportioned

    This answer follows the same pattern of reasoning as the stimulus, so it’s the correct answer.
  4. D
    Not all public buildings Remaining source text redacted.
    Why choice D is not credited
    This answer has two some premises, so it doesn’t match up with the stimulus.
  5. E
    Although some cathedrals are Remaining source text redacted.
    Why choice E is not credited
    This answer has the same quantifiers and conditionals as the stimulus, so we need to dive into the diagram:

    Cathedral --some-- ~Built of stone

    Cathedral → ...and we’re out, as the sufficient condition of the conditional is shared with the some statement, so a valid inference is possible.

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