LSAT 159 | Section 1 | Logical Reasoning: Q23

LR Question 23 Explanation

QUESTION TEXT: During last year’s flu season no one who was vaccinated …

QUESTION TYPE: Parallel Reasoning

CONCLUSION: No student at SHS will get the flu this season.

REASONING: Last year, no one who was vaccinated got the flu. This year, everyone is vaccinated.

ANALYSIS: The argument follows this pattern:

1. Before, no X person got outcome Y.
2. Now, everyone in group Z is X.
3. So no one in group Z will get outcome Y.

It uses what happened before as if it shows a general rule, then applies that rule to a new group.

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1. CORRECT. This follows the same structure. Before, everyone who did something (vaccination/repellent) avoided an outcome (flu/bitten), so since everyone is doing it now, no one will get that outcome.
2. This is about continuity of maintenance on the same object, not a rule applied from one group to a different group.
3. All premises and the conclusion here are about last year only. There’s no future prediction.
4. This is an argument about the same set of items, there’s no past pattern to future prediction.
5. This is a conditional argument that doesn’t follow the timeline and patterns structure.