PrepTest 109

[lcid:3535] Prep Test 109 LSAT — Logical Reasoning — S4 Logical reasoning

Question prompt

Essayist: Every contract negotiator Remaining source text redacted.
Why the credited answer is right

Credited answer: A

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

Question Type

Must Be True Questions

Answer choices

  1. A
    Every contract negotiator has Remaining source text redacted.
    Why choice A matches the stem
    Correct. Argument or Facts:
    Facts

    Question Type:
    Must Be True

    Stimulus Summary:
    Contract negotiator → Been lied to
    Tell a lie → Practicing deception
    Been lied to → Has told a lie

    Answer Anticipation:
    This stimulus features three conditional statements that, tenses aside, can be chained together.

    The first clause uses "every" to introduce a sufficient assumption; the second uses "whoever" for the same purpose. Any word that establishes 100% of a group has a characteristic can be diagrammed using conditional logic.

    It's also important to note the shift between the first and second clause—the first is about being lied to, the second is about telling a lie. Be sure you noted that!

    Finally, the third statement uses "anyone" as a sufficient condition indicator.

    If we ignore the tenses (which don't matter here—someone who has told a lie was practicing deception at the time), we can chain these together and take the contrapositive:
    Contract negotiator → Been lied to → Told a lie → Practiced deception
    not Practiced deception → not Told a lie → not Been lied to → not Contract negotiator

    Let's find an answer that lines up with these chains, either in their entirety or a portion of them.

    Answer Explanation:
    Contract negotiator → Practiced deception. This represents the inference made from the entire conditional chain, so it's the correct answer.

    Key Takeaway:
    Practice those conditional skills! There's no better feeling than getting to the last page of an LR section feeling as if you don't have enough time to get to both questions, and then knocking the first one out in under a minute because you're rock solid on conditional logic.
  2. B
    Not everyone who practices Remaining source text redacted.
    Why choice B is not credited
    Incorrect. Practice deception-some-not Told a lie. First, this answer is a some statement because "not everyone does" is the same as saying "some don't." With that noted, this answer could be true since Practice deception isn't sufficient for anything, but it's not definitively supported by the conditionals.
  3. C
    Not everyone who lies Remaining source text redacted.
    Why choice C is not credited
    Incorrect. Told a lie-some-not Practicing deception. The second conditional guarantees that everyone who tells a lie is practicing deception, so this answer is contradicted by the stimulus.
  4. D
    Whoever lies to a Remaining source text redacted.
    Why choice D is not credited
    Incorrect. This answer ties the lies to a contract negotiator, but they're relevant only to the first conditional, not the others.
  5. E
    Whoever lies to anyone Remaining source text redacted.
    Why choice E is not credited
    Incorrect. Told a lie → Been lied to. This answer is a reversal of the last conditional in the stimulus.

What this tests

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