Logical ReasoningDifficulty: Hard

PT159 S1 Q21 ExplanationProfessor O’Brien: Any of my students who heard

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

TopicsFlaw

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Stimulus

Professor O’Brien: Any of my students who heard Mercado’s lecture from the beginning would have thought it was fascinating, and I know that some of my students did think it was fascinating, have heard it from the beginning.

What this question is testing

Flaw

Your task

Describe the reasoning error the argument actually commits.

Common trap

Answers that name a real logical flaw the argument doesn't actually make.

Winning move

Articulate the gap in the reasoning yourself, then match it to the choice that describes that 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
21.

Professor O’Brien’s argument does not follow logically from its premises because of

Answer choices, explained

  1. Trap11% picked this

    some of Professor O’Brien’s students are very interested in Mercado’s work but were unable to

  2. Trap11% picked this

    many people who are not Professor O’Brien’s students did not think that the lecture was fascinating, even though they

  3. Trap7% picked this

    some of Professor O’Brien’s students were a few minutes late for the lecture and did not

  4. Correct59% picked this

    no one who heard the lecture from the beginning and thought that it was fascinating was one

    Why this is right

    Answer D is correct.

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

  5. Trap13% picked this

    not everyone who arrived at the lecture on time was able to hear the entire lecture because of disruptions caused by those

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