Logical Reasoning · Principle

PrepTest 155 · Section 4 · Question 13

Phase 1 (your first ~400 questions): read the guidance, then answer. No clock.

Step 1 · Pre-Question Guidance · read this first

Question type

Principle

The one idea it tests

To justify 'we have the right to do this,' the principle must hand over the right when exactly the conditions the arguer showed are met.

The basic logic

Someone objects that a requirement is not allowed. The arguer answers by showing two good features of the plan and concludes the objection is wrong. The principle should say: if the plan has those features, the requirement is allowed.

Tiny words that decide it

“if”
“and”
“right”

Playground logic

Some kids say Ms. Rivera has no right to make everyone buy the class planner. She answers: the price is fair, and it helps every student. Top bun: she does have that right. The secret sauce is a rule: fair price plus benefit to all means the requirement is allowed.

Step 2 · The kid story

The Planner Uprising

Ms. Rivera held up a shiny blue planner. "Starting Monday, every student needs one of these." Marcus shot up his hand. "Objection! You can't make us buy stuff!" Ms. Rivera smiled. "It costs the same as at the store, not a penny more. And the small profit pays for our field trip to the aquarium, which everyone goes on. Plus, planners keep homework from vanishing." Tommy whispered, "My homework vanishes into my candy drawer." Frankie and Sharon immediately started debating. "Fair price!" said Frankie. "Helps everybody!" said Sharon. "But does that give her the RIGHT?" Lulu wrote it down: She has the right IF the price is fair AND it helps everyone. That's the rule she needs.

Step 3 · Try the model question

Some students say Ms. Rivera is not allowed to make everyone buy the class planner. But they are mistaken. Her price is fair, and the requirement helps every student by funding a class trip and keeping homework organized.

Which principle, if true, does the most to support Ms. Rivera's reasoning?

Step 4 · The courtroom tale

The Mandatory Helmet Rule

"Your Honor," said a skate park owner, "these skaters claim I have no right to make them rent my helmets." Mr. Whitfield, representing the skaters, crossed his arms. "He has no such right." The owner continued. "The rental price matches every shop in town. And the rule helps every skater: fewer injuries, lower insurance, cheaper entry for all." The judge flipped through a thick book. "Our park code says an owner may require a rental if the price is fair and every user benefits." Mr. Whitfield sighed. "Fair price, check. Benefits everyone, check." "Then the owner has the right," said the judge. Mr. Whitfield handed out helmets on the way out, slightly embarrassed.

Step 5 · Work the real question

Open PrepTest 155, Section 4, Question 13 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

Find the top bun: the arguer says an objection is wrong, so something is allowed. List the reasons the arguer actually offered. Look for a principle whose 'if' part matches those reasons and whose 'then' part grants exactly what the conclusion claims. Run the Click Test. Check the direction of each conditional carefully, since a rule pointing the wrong way will not click.