Logical Reasoning · Necessary Assumption

PrepTest 145 · Section 2 · Question 6

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

Step 1 · Pre-Question Guidance · read this first

Question type

Necessary Assumption

The one idea it tests

If you show two camps will reject someone and conclude almost everyone will, you assume those two camps cover almost everyone.

The basic logic

The argument takes two groups, shows each will turn against a person, and concludes the person will have few backers overall. The hidden plank: there is no large third group outside both camps.

Tiny words that decide it

“almost all”
“few”
“either...or”

Playground logic

Nadia says Sharon will have hardly any friends after joining Marcus's Hall Monitor squad: Marcus's fans think Sharon tattled, and Marcus's critics dislike anyone on his squad. The secret sauce: nearly every kid is a fan or a critic. If most kids don't care about Marcus at all, the argument sinks.

Step 2 · The kid story

Sharon Joins the Hall Monitors

Last month, Marcus, self-appointed Chief of the Hall Monitors, wrote Sharon up for running in the hall. Sharon complained for weeks. Then, surprise: Marcus let the write-up go, and Sharon joined the Hall Monitors. Nadia predicted doom. "Almost all of Marcus's fans think Sharon really was running. And almost all of Marcus's critics hate anyone who joins his squad. So Sharon will have hardly any friends at school." Frankie, always ready to debate, jumped in. "Wait. What about the kids who don't care about Marcus at all? The first graders. The art kids. Kevin." Kevin looked up from his triceratops. "Who is Marcus?" Priya laughed. "Nadia's prediction only works if almost everyone is either a fan or a critic. If lots of kids are neither, Sharon will be fine."

Step 3 · Try the model question

Nadia: Sharon just joined Marcus's Hall Monitor squad. Almost all of Marcus's fans think Sharon broke the hallway rules. Almost all of Marcus's critics dislike anyone who joins his squad. So Sharon will have few friends at school.

Nadia's argument depends on assuming which one of the following?

Step 4 · The courtroom tale

The Case of the Lonely Baker

Mr. Whitfield faced the jury. "The bakery owner joined the rival chain's board. Almost every loyal customer of the chain thinks she once copied their recipe. Almost every fan of local shops scorns anyone who works with the chain. The plaintiff concludes her bakery will lose nearly all its customers." He snapped a suspender. "But Your Honor, the town's survey shows that most residents buy bread wherever is closest and have no opinion about the chain at all." The judge nodded. "The prediction only holds if almost everyone sits in one of those two camps. A big middle group breaks it. Damages for lost customers denied."

Step 5 · Work the real question

Open PrepTest 145, Section 2, Question 6 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

Identify the conclusion about overall support. List the groups the premises discuss and what each will do. Ask: do these groups cover nearly everyone? If not, the conclusion leaks. Use the Pull the Plank test: negate each answer and see whether the argument falls. Skip answers about whether the person was guilty, moral judgments about the deal, or claims about policy outcomes that the reasoning never uses.