Logical Reasoning · Inference (Must Be True)

PrepTest 144 · Section 2 · Question 13

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

Step 1 · Pre-Question Guidance · read this first

Question type

Inference (Must Be True)

The one idea it tests

A 'some are now refusing' statement guarantees only that not all of them are doing the thing.

The basic logic

Translate the statement into quantifiers. 'Some of group X are not publicly doing Y' must mean 'not all of group X are publicly doing Y'. Do not upgrade refusing into opposing, and do not invent a change of mind.

Tiny words that decide it

“some”
“not all”
“now”
“refusing”

Playground logic

Lulu's lunchbox holds one thing: some of last year's chess club kids are refusing to sign up for checkers. The only snack that fits is 'at least one chess club kid hasn't signed up for checkers'; anything about hating checkers or most kids is outside the lunchbox.

Step 2 · The kid story

The Checkers Holdouts

Last year, a bunch of kids joined the chess club with huge enthusiasm. Owen made badges. Nadia made snacks. This year Ms. Rivera started a checkers club. Lulu reported from her clipboard: "Some of the kids who joined chess last year are refusing to sign up for checkers." Marcus jumped up. "So most of them hate checkers!" Lulu shook her head. "I said some. Not most." Marcus tried again. "So they hate checkers, then." "Refusing to sign up isn't hating," Lulu said. "Maybe they're busy. Maybe they have dentist appointments." Priya sipped her juice box. "Here's what's guaranteed. Not every chess kid has signed up for checkers. That's all your clipboard proves." Lulu smiled and underlined it twice.

Step 3 · Try the model question

Lulu: Some of the students who eagerly joined the chess club last year now decline to join the new checkers club.

If Lulu's statement is true, which one of the following must also be true?

Step 4 · The courtroom tale

The Case of the Missing Signatures

The prosecutor, Mr. Grubb, thundered: "Some members of the garden society are refusing to sign the new fence petition. Clearly, they are enemies of fences!" Mr. Whitfield stood up slowly. "Your Honor, the evidence shows only that some members are not signing. It does not show they oppose fences. It does not show they ever changed their minds. Perhaps they simply dislike signing things in purple ink." Judge Lark peered over her glasses. "Mr. Grubb, what you have proven is this: not every garden society member has signed. That's it." Mr. Grubb sat down, muttering about purple ink.

Step 5 · Work the real question

Open PrepTest 144, Section 2, Question 13 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

Read the single statement and mark its quantifier and its exact verb. Rewrite it as a 'not all' sentence. Then check each choice against the lunchbox: does the statement force this to be true? Cross out choices that strengthen the verb, add a change of mind the statement never mentions, or flip which group is being described. The right answer usually sounds modest.