PrepTest 117

[lcid:3567] Prep Test 117 LSAT — Logical Reasoning — S4 Logical reasoning

Question prompt

Political theorist: For all Remaining source text redacted.
Why the credited answer is right

Credited answer: C

The notes below walk through why it fits the stem and how to eliminate the rest.

Argument or Facts

Argument

Valid or Flawed

Flawed

Question Type

Strengthen with Sufficient Premise Questions

Stimulus Summary

All members strong in foreign policy → Respond aggressively to problems
Respond aggressively to problems → All members perceive problem as grave
EU: ~All agree problem threatens economy → ~All members perceive problem as grave
Therefore - EU: ~All members strong in foreign policy

Answer Anticipation

Let’s start by going over our diagram from the Summary.
The first sentence sets up what a group “must do” to be strong in foreign policy, so that’s a requirement - a necessary condition. The second sentence has a standard conditional word (“only if” = necessary condition), but there is some trickery to it - it refers back to the earlier statement (“will do so”), requiring us to figure out what term it’s referring to - here (and almost always), it’ll be the one immediately preceding it. In the third premise, we treated “unless” as “if not” - if you ended up with the contrapositive of our diagram, no harm, no foul.
Then, finally, we get the conclusion - which isn’t conditional. At this point, we can determine that the flaw here is that the premises are all conditional and will presumably chain together, but the argument will fail to establish an absolute statement that “triggers” the chain, allowing the absolute conclusion to be drawn. Note that we made sure to “diagram” the conclusion to match with the term in the conditional.
With that done, we need to work with the conditionals to get them to line up with the conclusion. Since that conclusion is a negation of the sufficient condition of the first premise, we need to take the contrapositive of that and any other statement that will chain together after contraposing it:
~Respond aggressively to problems → ~All members strong in foreign policy
~All members perceive problem as grave → ~Respond aggressively to problems
EU: ~All agree problem threatens economy → ~All members perceive problem as grave
These all chain together, ending with ~All members strong in foreign policy. We can trigger this statement at any point along the chain to guarantee that the conclusion is true, but Strengthen with Sufficient Premise questions almost always use all premises (at least, when none are extraneous or “branch off” of the conditional chain), so we should be open to any of the terms being established while anticipating:
~All agree problem threatens economy
Or, in non-conditional language, not all members of the EU will agree that any problem threatens the economy (or there will always be some members who believe that a given problem doesn’t threaten the economy).

Answer choices

  1. A
    Countries that refuse to Remaining source text redacted.
    Why choice A is not credited
    First, the stimulus is about countries in an alliance. Second, this answer is relative - “more aggressively” - which doesn’t establish that either type of country does or doesn’t respond aggressively.
  2. B
    Countries become less aggressive Remaining source text redacted.
    Why choice B is not credited
    The relative nature of this answer (“less aggressive”, “greater wealth”) means that it doesn’t line up with the terms in the argument, and it is therefore out of scope. Additionally, talking about having more to lose and “becoming” less aggressive are both concepts that are not mentioned in the argument.
  3. C
    Problems that appear to Remaining source text redacted.
    Why choice C matches the stem
    This answer matches our anticipation. If this is true, we can say that for the EU, ~All agree problem threatens economy, since there will be disagreement for all problems. This answer “triggers” the conditional chain and allows the conclusion to be drawn, and it is therefore correct.
  4. D
    European Union member countries Remaining source text redacted.
    Why choice D is not credited
    This answer does provide a relationship directly relevant to the conclusion - any EU country that doesn’t see the economic relevance of a problem will generally be weak in foreign policy, and thus any such nation would mean that not all of the member countries of the EU are strong in foreign policy. Where this answer falls short is that it doesn’t establish that any such country exists! It’s still conditional, and the conclusion isn’t, so we can’t use more conditional statements to establish it (outside of very rare circumstances).
  5. E
    Alliances that are economically Remaining source text redacted.
    Why choice E is not credited
    The argument is about whether countries in an alliance are strong or weak in foreign policy, not whether the alliance itself is responsible for that strength/weakness, so this answer is out of scope.

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