LSAT 111 | Section 4 | Logical Reasoning: Q23

LR Question 23 Explanation

QUESTION TEXT: The higher the altitude, the thinner the air…

QUESTION TYPE: Parallel Reasoning

CONCLUSION: The air is thinner in Mexico City than in Panama City.

REASONING: Air is thinner at higher altitudes. Mexico City is higher than Panama City.

ANALYSIS: This is a good argument. Air is always thinner at higher altitudes. It goes from sufficient to necessary, like answer choice D. Answer choice E goes from necessary to sufficient.

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1. This is a bad argument. We get wiser as we get older. But this doesn’t tell us how wise we are to start with. A 70 year that started with little wisdom might be less wise than a 27 year old who started with a lot of wisdom.
2. This is a bad argument because it doesn’t tell us who beat their eggs whites the longest.
3. This is a bad argument. It goes from statistics about the general population to a specific marathon runner, Charles. Charles might be slower even if marathon runners are faster on average.
4. CORRECT. This is a good argument. Any tree that is older than another will have more rings, so Lou’s tree must have more rings. 
5. This is a bad argument. It confuses necessary conditions and sufficient conditions. Bigger vocabulary makes a language harder but a harder language won’t necessarily have a bigger vocabulary.