Logical ReasoningDifficulty: Medium

PT135 S1 Q11 Explanation

Inspector: The only fingerprints

A free, expert breakdown of this official LSAT Logical Reasoning question.

TopicsParallel Flaw

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Stimulus

Inspector: The only fingerprints on the premises are those of the owner, Mr. Tannisch. Therefore, whoever now has his have worn gloves.

What this question is testing

Parallel Flaw

Your task

Break the argument into its conclusion and evidence, then do exactly what the question stem asks with that structure.

Common trap

Answers that sound relevant to the topic but don't connect to the argument's actual reasoning.

Winning move

Predict what a right answer must do, then test each choice against the conclusion-evidence gap.

Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.

The question
11.

Which one of the following exhibits a flaw in its reasoning most similar to that in

Answer choices

  1. Correct76% picked this

    The campers at Big Lake Camp, all of whom became ill this afternoon, have eaten food only from the camp cafeteria. Therefore, the cause

    Why this is right

    There is a curious fact, "why did everyone at camp get sick", a leading suspect "they've only eaten at the cafeteria", and then a conclusion that bizarrely ignores this suspect and looks elsewhere.

    Skill tested: Parallel Flaw · how this choice captures the argument's function is the move to repeat next time.

  2. Bad Conclusion Match3% picked this

    The second prototype did not perform as well in inclement weather as did the first prototype. Hence, the production of the second prototype might

    The original conclusion was sure of itself. That was the flaw. This conclusion is super softly worded. It's pretty reasonable to say a curious fact might be explained by a given causal hypothesis.

  3. Not Part to Whole2% picked this

    Each of the swimmers at this meet more often loses than wins. Therefore, it is unlikely that any

    This commits a part to whole flaw: because each swimmer loses most of the time, the author concludes that the no one from the batch is likely to win. The original argument wasn't a Part to Whole flaw; it was a Causal flaw.

  4. Plausible Hypothesis18% picked this

    All of Marjorie's cavities are on the left side of her mouth. Hence, she must chew more on the left

    This has a curious fact and arrives at a certain causal conclusion, but this doesn't match the original argument because this conclusion actually calls out the leading suspect. Since all the cavities are on the left, the hypothesis that she eats more on that side is the more obvious possibility.

  5. Bad Conclusion Match Not Comparison Flaw2% picked this

    All of these tomato plants are twice as big as they were last year. So if we grow peas, they will probably be twice

    This conclusion is conditional, whereas the original argument's conclusion was causal. This argument is making a comparison flaw: what was true of tomato plants will also be true of pea plants. The original argument make a causal flaw.

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