Logical reasoning PrepTest 103 · Section 3 · Question 15

Question prompt

A person's dietary consumption 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

Facts

Valid or Flawed

NA

Question Type

Must Be True Questions

Stimulus Summary

Relationship - Increases to dietary cholesterol/fat is proportional to blood cholesterol until threshold
Post-threshold relationship - Blood cholesterol levels increase gradually
Threshold - ¼ of average North American diet

Answer Anticipation

The stimulus here presents a series of relationships, along with a discussion of a threshold, that is then compared to the current consumption level of the average North American. These statements all build together, so we should see how they all line up and figure out what inferences we can draw.
Let’s start with this threshold. We know that the average North American is very much over the threshold - that threshold is ¼ of the North American diet. So what do we know about people over the threshold? Their serum cholesterol levels increase only gradually, even if dietary fat/cholesterol goes up quite a bit. And since they’re above the threshold, the initial relationship about what happens below the threshold is out of scope.
So what can we infer? That the average North American - who is over the threshold - won’t see a proportional relationship between their consumption of fat/cholesterol and their serum levels. Instead, they’ll see a gradual increase, no matter how much extra fat/cholesterol they eat. Let’s find an answer reflecting that.

Answer choices

  1. A
    The threshold can be Remaining source text redacted.
    Why choice A is not credited
    There’s no indication that the threshold can be changed.

  2. B
    People who consume an Remaining source text redacted.
    Why choice B is not credited
    This answer is contradicted by the stimulus. We know that the average North American is over the threshold, so their serum levels will increase gradually regardless of their consumption.

  3. C
    People who consume half Remaining source text redacted.
    Why choice C matches the stem
    North Americans are, on average, eating 4x the threshold amount of fat/cholesterol. So someone eating half as much is at 2x the threshold. Both groups are consuming an amount that means their serum levels aren’t proportional to the fat/cholesterol consumed, so there won’t be a 1:1 relationship there, and thus the 2x group won’t have half the serum amount as the 4x group. This answer is supported by the stimulus (and a bit more math than we like…), so it’s the correct answer.

  4. D
    Serum cholesterol levels cannot Remaining source text redacted.
    Why choice D is not credited
    The stimulus notes that diet is “one of the most important factors” affecting serum cholesterol, but that’s not the same as being the only factor, or even the only important factor, so this answer isn’t supported.

  5. E
    People who consume less Remaining source text redacted.
    Why choice E is not credited
    The stimulus doesn’t discuss decreasing serum cholesterol, just increasing it. Even if we infer that the proportional relationship flows in both directions, it would suggest people could lower their serum cholesterol by eating less cholesterol/fat.

What this tests

Question analytics

Based on historical answer selection rates for this question.

Answer choice distribution

  1. A 12%
  2. B 6%
  3. C Credited 78%
  4. D 2%
  5. E 2%

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