Logical ReasoningDifficulty: Medium

PT21 S2 Q10 Explanation

The increase in the price of jet

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

TopicsMust be True

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Stimulus

The increase in the price of jet fuel is due to a sharp decrease over the past year in the supply of jet fuel available relative to demand. Nonetheless, the amount of jet today than it was last year.

What this question is testing

Must be True

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
10.

If the statements above are true, which one of the following conclusions can be properly drawn on the

Answer choices

  1. Correct72% picked this

    The demand for jet fuel has increased over the

    Why this is right

    As we discussed above, since supply is higher this year, but supply relative to demand is lower this year, that proves that demand must have increased even more than supply increased.

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

  2. Out of Scope: efficiency of engines7% picked this

    The fuel efficiency of jet engines has increased over the

    The passage is never talking about how much jets are used, so we have no way to judge the efficiency of the engines.

  3. Out of Scope: number of flights13% picked this

    The number of jet airline flights has decreased over the

    We have no information about number of flights. This is just speculating a backstory for why there is more fuel available, but there could be 15 possible explanations. None of them must be true.

  4. Out of Scope: cost of refining2% picked this

    The cost of refining petroleum for jet fuel has increased over

    We don't have any information about refining costs. This would just be speculating some reason for why supply has gone up or supply relative to demand has gone down.

  5. Out of Scope: petroleum5% picked this

    The supply of petroleum available for jet fuel has decreased over

    We never discuss petroleum, so we can't derive any must be true inference about it.

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