Logical Reasoning · Sufficient Assumption

PrepTest 119 · Section 2 · Question 4

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

Step 1 · Pre-Question Guidance · read this first

Question type

Sufficient Assumption

The one idea it tests

Find the magic key that makes the premises force the conclusion with a click.

The basic logic

The conclusion says some wins are harmless. The premises say the winners got the most votes but not over half, and only won when rivals squabbled. Nothing yet links 'most but not over half' to 'cannot cause harm'. The key is a rule saying that groups with that kind of win never bring about the feared change, directly or indirectly.

Tiny words that decide it

“no threat”
“not”
“only when”
“never”

Playground logic

Marcus says the pineapple pizza fans winning the snack poll poses no danger to the menu, because they got the most votes but not more than half, and only won when the other kids split their votes. The secret sauce that clicks it shut: a choice that wins with less than half never gets served, in any way.

Step 2 · The kid story

The Pineapple Panic

Kevin's pineapple pizza fans won the Friday snack poll. The cafeteria buzzed with worry. "Pineapple on everything!" someone wailed. Marcus raised a hand. "Relax. This is zero danger to our lunch menu. Pineapple got the most votes, sure, but not more than half. And it only won because the pepperoni kids and the cheese kids kept fighting each other and split their votes." Lulu frowned at her clipboard. "Wait. Why does 'most but not more than half' mean zero danger?" Marcus opened his mouth, then closed it. Priya sipped her juice box. "You need one more rule, Marcus. Something like: a snack that wins with less than half the votes never ends up on the menu, not even sneaking in some other way. Then your argument clicks."

Step 3 · Try the model question

Marcus: The pineapple pizza win poses no danger to the lunch menu. Pineapple got the most votes but not more than half. Also, it won only when the other groups were busy fighting each other.

Which one of these, if assumed, makes Marcus's conclusion follow logically?

Step 4 · The courtroom tale

The Garden Club Vote

"Your Honor," said Mr. Whitfield, "the Cactus Lovers winning the garden club vote is no danger to the rose beds. They got the most votes but not a majority, and they won only because the rose fans and tulip fans bickered." Judge Ortiz peered over her glasses. "Counsel, those are facts about the vote. Your conclusion is about the rose beds. What connects them?" Mr. Whitfield tugged his suspenders. "Ah. I must also assume that a group winning without a majority never changes the garden, not directly, not by persuading others later." The judge nodded. "With that rule, your argument locks shut. Without it, the roses are still at risk."

Step 5 · Work the real question

Open PrepTest 119, Section 2, Question 4 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

Write the conclusion and the premises as short phrases. Notice the gap: the premises talk about the kind of win, the conclusion talks about harm. Predict a bridge rule connecting that kind of win to no harm. Plug each choice in and see whether the conclusion now must follow. Cut choices that only make the conclusion more likely, that talk about voters or other systems, or that say what sometimes happens.