Logical Reasoning · Sufficient Assumption

PrepTest 146 · Section 2 · Question 3

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

Bridge the gap between 'written from one point of view' and 'not worth much to people with another point of view.'

The basic logic

The premises say the material is built from viewpoint X and the users lack viewpoint X. The conclusion says the material is not worth much to them. The magic key is a rule linking a mismatch of viewpoint to limited usefulness.

Tiny words that decide it

“almost all”
“most”
“unless”
“limited”

Playground logic

Grandpa's cookbook is written for a big oven, and the cooking club only has toaster ovens. To conclude the recipes are not worth much, Priya needs the secret sauce: a recipe is not worth much unless it fits the oven the cook really has.

Step 2 · The kid story

The Big Oven Problem

The fifth grade cooking club found Grandpa's old cookbook in the school kitchen. Nadia flipped through it. "Almost every recipe says to use a big oven with four racks," she read. Owen looked around. The club only had small toaster ovens, and so did most of the kids at home. "So this book won't help us much," Owen said. Marcus, ever the detective, crossed his arms. "Wait. Why not? Food is food." Priya set down her juice box. "Owen's right only if one more thing is true," she said. "A recipe is not much help unless it's written for the oven you actually have." Marcus thought about it. He remembered last week's cupcakes, which came out burnt on top and gooey in the middle. "Okay," he admitted. "Click."

Step 3 · Try the model question

Almost every recipe in Grandpa's cookbook is written for a big four rack oven. Most kids in the cooking club have only toaster ovens. So the cookbook is not worth much to most of the club.

Adding which one of these would make Owen's conclusion airtight?

Step 4 · The courtroom tale

The Case of the Left Handed Scissors

Mr. Whitfield addressed the jury. "Nearly every pair of scissors this shop sells is designed for right handed people. Most members of the Lefty Crafters Guild are left handed." He paused. "Therefore the shop's scissors are not worth much to most of the guild." The judge tapped her pen. "That only works, counselor, if a tool is not worth much unless it is designed for the hand of the person using it." Mr. Whitfield bowed. "Precisely, Your Honor. That is the rule I am resting on." The judge wrote it down. "Then the conclusion clicks."

Step 5 · Work the real question

Open PrepTest 146, Section 2, Question 3 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

Find the gap between the premise words and the conclusion words. Here the premises talk about viewpoints and who has them, while the conclusion talks about usefulness. Look for a choice that ties those two ideas together as a rule, ideally with an 'unless' or 'only if' shape. Then do the Click Test: add it to the premises and see if the conclusion is forced. Discard choices about readers' wishes or ambitions.