Logical Reasoning · Weaken

PrepTest 128 · Section 2 · Question 7

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

Step 1 · Pre-Question Guidance · read this first

Question type

Weaken

The one idea it tests

A prediction that people will switch because the new option is cheaper ignores hidden costs of switching.

The basic logic

The conclusion predicts a big switch. The evidence is all about the price and quality of the materials. Look for a cost or obstacle that comes with switching, one the evidence never counted.

Tiny words that decide it

“within”
“most”
“rather than”

Playground logic

Kevin's top bun says most kids will switch to dry-erase boards soon. His patty is all about board prices and sturdiness. To pop it, show a hidden switching cost, like pricey markers that every board needs.

Step 2 · The kid story

Kevin's Big Prediction

Kevin stood on a chair at lunch. "Mark my words! By next month most kids will use dry-erase boards instead of paper notebooks." Why? "Notebooks keep getting pricier and flimsier. Dry-erase boards keep getting cheaper. And boards never rip, never get soggy, never lose pages!" Marcus nodded hard. "Airtight." Priya sipped her juice box. "Kevin, what do you write on a dry-erase board with?" "Special markers, obviously." "And how much do those cost?" Tommy checked the school store list. "Whoa. The markers cost a lot, and they dry out in about a week." Lulu wrote it down. "So the board is cheap, but using it isn't." Kevin climbed off the chair slowly. "Okay, maybe not everyone by next month."

Step 3 · Try the model question

Kevin: Within a month, most kids in our school will use dry-erase boards instead of paper notebooks. Notebooks are getting pricier and flimsier, while dry-erase boards are getting cheaper. Also, unlike notebooks, boards never rip.

Which choice, if accurate, does the most damage to Kevin's reasoning?

Step 4 · The courtroom tale

The Bicycle Fleet

A delivery firm's lawyer predicted in court: "Within five years, most couriers in this city will ride electric scooters instead of bicycles. Bikes are getting costlier; scooters are getting cheaper." Mr. Whitfield stood, adjusting his suspenders. "Your Honor, one small matter. Each courier must take a licensing course to ride a scooter for work, and that course costs more than a year's pay for most of them." The judge raised an eyebrow. "So the scooter is cheap, but getting on it is not." The lawyer frowned. "I hadn't counted that."

Step 5 · Work the real question

Open PrepTest 128, Section 2, Question 7 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

Find the prediction and notice that the evidence only compares the two materials themselves: cost, quality, durability. Then hunt for a choice that adds a cost or barrier tied to making the switch, something the evidence ignores. Cross off choices that hit both options equally, that add another plus for the new option, or that talk about overall numbers without touching which option wins.