LSAT Explanation PT 23, S2, Q25: Economist: No economic system that is
LSAT Question Stem
The pattern of reasoning exhibited by the economist's argument is most similar to that exhibited by which one of the following?
Logical Reasoning Question Type
This is a Parallel question.
Correct Answer
The correct answer to this question is B.
LSAT Question Complete Explanation
This is a "Parallel Reasoning" question. The economist's argument can be outlined as follows:
1. Centrally planned economy -> / Efficiently allocate resources
(Contrapositive: Efficiently allocate resources -> / Centrally planned economy)
2. Debt < 5% GDP -> Efficiently allocate resources
(Contrapositive: / Efficiently allocate resources -> Debt ‚â• 5% GDP)
3. Conclusion: Centrally planned economy -> Debt ‚â• 5% GDP
This argument is valid. By combining premise (1) with the contrapositive of premise (2), we get the conclusion. We need to find an answer choice with the same pattern of reasoning. Any answer choice with flawed reasoning is not the correct answer!
Answer choice (A): This answer choice has valid reasoning, but the logical chain is based on the relationship of a subgroup to a main group (some mammals are bats), which is not the same logic as in the stimulus.
Answer choice (B): This is the correct answer choice.
1. Air pollution problems -> Large concentration of automobiles
(Contrapositive: / Large concentration of automobiles -> / Air pollution problems)
2. Rural districts -> / Large concentration of automobiles
(Contrapositive: Large concentration of automobiles -> / Rural districts)
3. Conclusion: Rural districts -> / Air pollution problems
This is valid reasoning, just like the stimulus. We get this conclusion by combining premise (2) with the contrapositive of premise (1). This is the correct answer choice.
Answer choice (C): The conclusion in this answer choice involves the qualified term "unlikely" rather than a definite statement, like the conclusion in the stimulus. This cannot be the correct answer choice.
Answer choice (D):
1. Famous rock star -> Own record company
2. Famous rock star and Receive extra company profits -> Own Record Company
The correct conclusion is: Famous rock star -> Receive extra company profits.
However, the conclusion stated is: Famous rock star -> Receive large regular royalties. This is not the right conclusion.
This logic is flawed, so this is not the correct answer choice.
Answer choice (E): The first premise alone (every mutual fund manager knows an insider trader) is enough to establish the conclusion: There is no mutual fund manager who is unknown to every insider trader. (Assume that "know" is a bilateral relation, so if X knows Y, then Y knows X.) This logical form is not like the stimulus.