LSAT 128 | Section 3 | Logical Reasoning: Q2

LR Question 2 Explanation

QUESTION TEXT: Because metallic mirrors absorb some light …

QUESTION TYPE: Identify the Conclusion

CONCLUSION: Metallic mirrors can’t be used when minimizing energy loss is important.

REASONING: They absorb light and waste energy.

ANALYSIS: To identify conclusions, you have to find the statement that is supported by everything else and supports nothing else.

Sentences 1 and 2 are the reasoning/premises to support the conclusion, which is in sentence 3.

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1. This is too specific. The argument’s claim is that metallic mirrors are unsuitable for any energy-sensitive application, not just high-powered lasers.
2. This is a premise, not the conclusion. The argument builds on this to establish why they are unsuitable for energy-sensitive applications.
3. This may be true, but it’s at best a background assumption or an inference. If it’s not mentioned, it definitely can’t be the conclusion.
4. The argument never claims that energy waste is the most significant disadvantage, just that it’s a relevant issue for certain applications. There’s no ranking of disadvantages going on here.
5. CORRECT. This best expresses the conclusion, as it captures both the energy loss problem and the resulting unsuitability. This is expressed in sentence 3 of the stimulus.