Logical ReasoningDifficulty: Hard

PT15 S3 Q9 Explanation

Chronic fatigue syndrome, a condition

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

TopicsFlaw

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Stimulus

Chronic fatigue syndrome, a condition that afflicts thousands of people, is invariably associated with lower-than-normal concentrations of magnesium in the blood. Further, malabsorption of magnesium from the digestive tract to the blood is also often associated with some types of fatigue. These facts in themselves demonstrate that treatments that raise an effective cure for the fatigue involved in the syndrome.

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
9.

The argument is most vulnerable to which one of the

Answer choices

  1. Trap21% picked this

    It fails to establish that lower-than-normal concentrations of magnesium in the blood are invariably due

  2. Correct72% picked this

    It offers no evidence that fatigue itself does not induce lowered concentrations of magnesium

    Why this is right

    Answer B is correct.

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

  3. Trap5% picked this

    It ignores the possibility that, even in people who are not afflicted with chronic fatigue syndrome, concentration of

  4. Trap1% picked this

    It neglects to state the exact concentration of magnesium in the blood which is considered

  5. Trap1% picked this

    It does not specify what methods would be most effective in raising the concentration of

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