LSAT 153 | Section 3 | Logical Reasoning: Q3

LR Question 3 Explanation

QUESTION TEXT: Columnist: Although it is our civic duty to protect the…

QUESTION TYPE: Sufficient Assumption

CONCLUSION: We should not divert high-tension power lines away from heavily populated areas.

REASONING: We should only protect the population against well-substantiated threats to public health.

ANALYSIS: The argument in a sufficient assumption question is missing something that allows for the conclusion to be properly reached. Therefore, the correct answer will be the bridge that links the reasoning and conclusion segments and makes the argument work as a whole. In this case, notice that we can reword “only protect against well-substantiated threats” to mean “do not need to protect against unsubstantiated threats”. Since our conclusion is that we don’t need to protect against power lines, the correct answer establishes power lines as an unsubstantiated threat.

___________

1. We have no reason to believe that the loss of high-tension power lines will cause the loss of electric power altogether. There may be other ways of bringing electric power to populated areas. Therefore, this statement is insufficient on its own.
2. The argument is trying to make a case on the basis of health-related concerns. Bringing in economic concerns is irrelevant to our argument.
3. The term “various modern practices” is vague and doesn’t explicitly reference high-tension power lines. We cannot assume that power lines are included.
4. CORRECT. See the analysis section. We connect our conclusion to our reasoning like so: We only protect against substantiated threats, power lines are not a substantiated threat, therefore we don’t have to reroute our power lines.
5. This is a separate issue. Studying the effects of power lines on people is separate from whether it is known to be a substantiated threat or not. We might think that the two are related, because we gain evidence about whether or not it is a threat through studying, but we only care about whether there is evidence right now. Compared to D, this answer is too far removed.

Recap: The question begins with “Columnist: Although it is our civic duty to protect the”. It is a Sufficient Assumption question. Learn how to master LSAT Sufficient questions on the LSAT Logical Reasoning question types page.