Logical ReasoningDifficulty: Medium

PT143 S3 Q14 Explanation

Branson: Most of the air pollution

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

TopicsParallel Flaw

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Stimulus

Branson: Most of the air pollution in this country comes from our largest cities. These cities would pollute less if they were less populated. So if many people in these cities were to move to country as a whole would be reduced.

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
14.

Which one of the following demonstrates most effectively by parallel reasoning that Branson's

Answer choices

  1. Bad Conclusion Match6% picked this

    Similarly, we could conclude that Monique spends most of her salary on housing. After all, people are bound to spend more on housing if

    The original conclusion was a conditional that had an outcome that sounds like it's reducing a problem. This conclusion is just a factual statement about where Monique spends most of her salary. It would be a good move to bail on this, simply from the bad conclusion, and only return to read the rest if no other answer pans out.

  2. Bad Evidence Match7% picked this

    Similarly, we could conclude that Karen's family would have more living space if they moved from an apartment to a single-family home. After all,

    The conclusion could potentially match: If they move from an apartment to a single-family home, they will have more living space. Does the premise make it seem like making this move would just re-allocate the "not having enough space" problem so that now there's less of it in the apartment and more of it in the single family home? No, partly because the family wouldn't own both homes. It's not like one of their accounts goes down while another goes up. More importantly, it's because single family homes actually have more space! Going from an apartment to a single-family home usually means you do have more space than before, so it might be a genuine solution to the problem, as opposed to the flawed solution that just re-allocates the problem into a different place.

  3. Bad Conclusion Match4% picked this

    Similarly, we could conclude that most of Ward's farm is planted with corn. After all, in Ward's county most of the fields that used

    The original conclusion was a conditional that had an outcome that sounds like it's reducing a problem. This conclusion is just a factual statement about what most of Ward's farm consists of. It would be a good move to bail on this, simply from the bad conclusion, and only return to read the rest if no other answer pans out.

  4. Correct71% picked this

    Similarly, we could conclude that Javier could consume fewer calories by eating for breakfast, lunch, and dinner only a portion of what he now

    Why this is right

    The conclusion could potentially match: If he moved a portion of his breakfast, lunch, and dinner into snacks, he would consume fewer calories. Does the premise make it seem like making this move would just re-allocate the problem rather than solve it? Yes! If you save half your breakfast, half your lunch, and half your dinner and then eat those portions as snacks, then you haven't reduced total calories at all. You've just re-allocated where those calories are found. In the original argument, we didn't reduce air pollution by moving some people from big cities to smaller cities ("Snack" cities, if you will). We just re-allocated that overall amount of pollution into different areas. This answer also contains a similar premise to "Most air pollution comes from largest cities", because it has "Most calories come from breakfast / lunch / dinner".

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

  5. Bad Evidence Match Topic Trap11% picked this

    Similarly, we could conclude that most of this city's air pollution would be eliminated if this city built a public transportation system. After all,

    The conclusion could potentially match: If we built a public transportation system, we could reduce the problem of air pollution. Air pollution? Wasn't that the topic of the original argument? Trap Alert! Trap Alert! Does the premise suggest that by building a public transportation system we would just be re-allocating a problem from one place to another? No, the evidence sounds like the solution would actually work. Switching cars for public transportation should actually cut down on pollution.

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