Logical Reasoning · Principle
PrepTest 158 · Section 4 · Question 21
Phase 1 (your first ~400 questions): read the guidance, then answer. No clock.
Step 1 · Pre-Question Guidance · read this first
- “unless”
- “every”
- “should”
- “anyone”
Playground logic
Ms. Rivera says the art show can't happen unless the stage gets fixed, the show will buy books that help every student, so every student should chip in. The secret sauce rule: whoever gains from what a project brings should chip in for that project.
Step 2 · The kid story
Quarters for the Stage
Ms. Rivera tapped the board. "Our art show can't happen unless the gym stage gets fixed. The art show will raise money for new library books. New library books help every single student. So, everyone, please put a quarter in the stage jar." Kevin raised his hand. "But I don't even draw. I only draw dinosaurs, and that doesn't count." Priya leaned over. "Do you read library books?" "Every day," Kevin said. "Dinosaur ones." "Then you gain from the show, and the show needs the stage. Ms. Rivera's rule is: if you'd gain from what the fix leads to, you chip in for the fix." Kevin dug in his pocket and found a quarter, a button, and half a pretzel. He offered all three.
Step 3 · Try the model question
Ms. Rivera: The art show will not happen unless the gym stage is repaired. The art show would raise money for new library books, and new library books would help every student. So every student should chip in for the stage repair.
Which rule, if accepted, best backs up Ms. Rivera's reasoning?
Step 4 · The courtroom tale
The Case of the Shared Bridge
In an invented county, the farmers' market could not open unless a footbridge over the creek was rebuilt. The market would bring fresh food that every family wanted. The county's lawyer told the judge, "So every family should pay a small bridge fee." Mr. Whitfield, for a grumpy family, objected. "My clients never cross that bridge, Your Honor!" The judge replied, "They'll eat the market's tomatoes, won't they? The county's rule is that whoever gains from what a project brings should help pay for it. Your clients gain. The fee stands." Mr. Whitfield sighed and adjusted his suspenders.
Step 5 · Work the real question
Open PrepTest 158, Section 4, Question 21 in your official copy from LSAC (for example in LawHub) and read it there.
Your answer
How to apply it
Lay out the chain: one thing depends on a project, that thing benefits everyone, so everyone should fund the project. Write the rule you would need in your own words before reading the choices. The right principle starts from what the premises supply (benefit from results) and ends exactly at the conclusion (should vote to fund). Check the arrow direction: the rule must carry you from the premises to the conclusion, not the other way.