Logical Reasoning · Sufficient Assumption

PrepTest 152 · 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

A rule closes one door but opens a side door; the missing link is that the side door actually leads to the bad result.

The basic logic

The top bun says a rule makes a bad outcome more likely. The patty shows one route is blocked but the rule causes a new behavior. The magic key connects that new behavior to the bad outcome. Run the Click Test: add it and the conclusion locks in.

Tiny words that decide it

“however”
“because”
“often”
“usually”

Playground logic

Ms. Rivera's fancy-lunch rule makes kids stash uneaten food in their desks (patty). The top bun says the rule increases wasted food. The magic key is that food stashed in desks ends up wasted.

Step 2 · The kid story

The Deluxe Lunch Rule

Ms. Rivera wanted less wasted food, so she made a rule: every lunch must have five food groups, cut into neat shapes. Nadia frowned. 'This rule will make MORE food get wasted.' Owen was confused. 'But nobody can toss food anymore. The lunch monitor watches the trash can like a hawk.' 'True,' said Nadia. 'Tossing is out. But five-group lunches are huge. Kids cannot finish them, so they hide the leftovers in their desks.' Marcus shrugged. 'So? Hidden is not wasted.' Priya tapped her juice box. 'That is exactly the gap. Nadia needs one more piece: that desk leftovers end up spoiled and thrown out later.' Kevin lifted his desk lid. A fuzzy green sandwich stared back. 'I think,' said Lulu, 'the gap is closed.'

Step 3 · Try the model question

Nadia: The five-food-group lunch rule will increase wasted food. Kids can no longer throw food away during lunch, since the monitor watches the trash. But because big lunches are hard to finish, kids often hide leftovers in their desks.

Which assumption, once added, would make Nadia's conclusion lock into place?

Step 4 · The courtroom tale

The Case of the Tangled Kite Strings

The park board made a rule: every kite string must be extra long. Lawyer Bea Tran objected. 'Your Honor, this rule will cause more broken kites. Short strings got kites snagged in the oak, but the park cut that oak down, so snags are now impossible. However, long strings tangle, so flyers often knot them together in a hurry.' The judge frowned. 'Knots, fine. Where do broken kites come in?' Mr. Whitfield, for the board, grinned. 'My point exactly, Your Honor. Knots are not broken kites.' Ms. Tran held up a ribbon of evidence. 'Then I add this: hurried knots snap in the wind, and the kite crashes.' The judge nodded. 'Now your chain reaches the end.'

Step 5 · Work the real question

Open PrepTest 152, Section 2, Question 3 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

Locate the top bun: a rule produces a bad result. Note which route the patty says is blocked and which new behavior the rule causes. Find the gap between that new behavior and the bad result in the conclusion. Pick the choice that bridges exactly that gap, using the Click Test. Drop choices that undercut a premise, add unrelated costs, or discuss a route the argument already closed.