PrepTest 102

[lcid:3506] Prep Test 102 LSAT — Logical Reasoning — S3 Logical reasoning

Question prompt

Congenial guests and a Remaining source text redacted.
Why the credited answer is right

Credited answer: D

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 / Sufficient & Necessary Questions

Stimulus Summary

Congenial guests AND Lots of good stuff to eat/drink → Successful dinner party Sylvia - Lots to eat/drink AND Congenial guests Therefore - Sylvia - Successful dinner party

Answer Anticipation

This argument features conditional logic, so you should have started off by thinking that there was likely going to be an illegal negation or reversal. Diagramming out the first sentence, we see that something “ensure[s]” another, meaning that the first thing is a sufficient condition for the second, hence our diagram. Then, it appears as if the next premise establishes the sufficient conditions are met, and it then concludes the necessary condition. So there’s no illegal reversal/negation here! When a conditional argument doesn’t feature a Sufficient/Necessary flaw, it’s likely that there’s a term shift between the conditional and either the triggering premise or the conclusion. If we dig in and check those against each other, we can see that the premise fails to fully establish one of the two sufficient conditions. It’s not that a lot of food and drink is enough to guarantee that part is a success - the food/drink must be “good.” In failing to establish that the sufficient condition is fully met, this argument is flawed. Let’s find an answer that has the same issue.

Answer choices

  1. A
    The right ingredients, properly Remaining source text redacted.
    Why choice A is not credited
    This argument is valid - if Emily bakes her cake in a reliable oven with the right, properly combined ingredients, then she will get a well-baked cake.
  2. B
    If corn is baked Remaining source text redacted.
    Why choice B is not credited
    This answer has George meeting the sufficient condition for a moist dish, so it doesn’t have the same flaw as the stimulus. Instead, this argument is flawed in that it assumes George is aware of what is sufficient to ensure he’ll get a moist dish, and that he’ll take action to make that happen.
  3. C
    Making pie dough using Remaining source text redacted.
    Why choice C is not credited
    Andrew met the sufficient conditions for a flaky crust, so this argument is valid.
  4. D
    If soup is made Remaining source text redacted.
    Why choice D matches the stem
    This argument fails to establish that Arnold’s meat stock was well-seasoned, so it doesn’t show that he fully met the sufficient conditions to ensure a welcome soup. This answer has the same flaw as the stimulus, so it’s the correct answer.
  5. E
    Fresh greens, carefully washed Remaining source text redacted.
    Why choice E is not credited
    This argument has an illegal negation, treating the failure to meet a sufficient condition (carefully washed greens) as guaranteeing the necessary condition (refreshing salad) can’t be met.

What this tests

Discussion

  • I got it right, but why? 2 replies

    Started by iHAVE33FLAWSandAcommonLSATflawAINTone

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