PrepTest 131
[lcid:3621] Prep Test 131 LSAT — Logical Reasoning — S2
Logical reasoning
Question prompt
At one sitting, 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.
Question Type
Strengthen with Necessary Premise Questions
Answer choices
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AThe calories and fat Remaining source text redacted.
Why choice A is not credited
Incorrect. The argument never discusses health, just calorie/fat content, so this answer is out of scope. -
BMost bagel eaters are Remaining source text redacted.
Why choice B is not credited
Incorrect. Awareness doesn't play into the totals consumed. Whether or not bagel eaters are fully aware of the calories/fat they're consuming, they are consuming it. Additionally, this answer doesn't play into any point of comparison between the two groups, so it's unlikely to be correct. -
CEating bagels instead of Remaining source text redacted.
Why choice C is not credited
Incorrect. Similar to answer choice (A), health effects are out of scope of this argument since it never discusses them. -
DThe typical doughnut eater Remaining source text redacted.
Why choice D matches the stem
Correct. Argument or Facts:
Argument
Valid or Flawed:
Flawed
Question Type:
Strengthen with Necessary Premise
Stimulus Summary:
Doughnut eater: 4 doughnuts, 680 calories/40g of fat
Bagel eater: 1 bagel, 500 calories/1-2g of fat; spreads that can raise calories/fat to doughnut range
Therefore, bagel eaters and doughnut eaters consume about the same amount of calories and fat.
Answer Anticipation:
First, LSAT, it's donut—get your pretentious spelling out of here!
Second, this argument very much features a comparison between bagel eaters and donut eaters, concluding that they are similar in their calorie and fat consumption. While bagels and donuts have different calorie/fat amounts (a difference), and consumers tend to eat different amounts of eat per sitting (another difference), the stimulus notes that the bagel eaters add cream cheese/butter to their bagels, raising that calorie and fat count up to the same level as the donuts. That seems like the argument is valid, right?
Well, remember other questions that have featured comparisons on the LSAT—frequently, the comparison will be incomplete—is there a source of calories and fat in either breakfast food, especially one that's already been raised but only for one of the two products? There is! The stimulus tells us that the typical bagel eater puts stuff on her bagel, but it doesn't discuss whether or not the typical donut eater puts spreads on his breakfast. It's possible that the donut eater is also adding, say, frosting and sprinkles, which could raise the total fat/calorie count even higher.
In raising a consideration for one of the products but not discussing if it factors into the other, this comparison is incomplete. The argument is relying on donut eaters not adding additional calories/fat to their food the same way that the bagel eater does.
Answer Explanation:
If the typical doughnut eater does add substances that increase fat/calories in the same way that bagel eaters do, then the argument falls apart. It's necessary to assume that they don't do this for the argument to work, so this is the correct answer.
Key Takeaway:
When an argument is based on a comparison between two groups, it will frequently discuss a characteristic of one group without relating it to the other. When that happens, the correct answer frequently deals with how that characteristic applies to the other group. Here, the stimulus discussed spreads for bagels, but not for doughnuts. The correct answer filled in that gap in the comparison. -
EMost typical doughnut eaters Remaining source text redacted.
Why choice E is not credited
Incorrect. The conclusion is about what individuals eat, and it clearly defines what a sitting is, so the argument doesn't require that people pick one type of breakfast food and stick with it. If most typical doughnut eaters are also bagel eaters, but they don't mix and match in the same sitting, the argument could still work. Even if they do occasionally eat both in one sitting, averages for when they don't could still be developed.
What this tests
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