Logical Reasoning · Inference

PrepTest 103 · Section 1 · 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 (Cannot Be True)

The one idea it tests

Turn the claims into arrows, then find the choice that crashes into an arrow.

The basic logic

Diagram: effective in the role leads to a certain trait, and having the opposite of that trait leads to never being effective. The impossible choice puts the opposite trait and effectiveness in the same person.

Tiny words that decide it

“all”
“must”
“never”
“CANNOT”

Playground logic

Frankie's arrows: great goalkeeper → shouts, and perfectly quiet → never a great goalkeeper. So a perfectly quiet great goalkeeper is the one thing that cannot exist. Everything else just has to avoid the crash.

Step 2 · The kid story

The Silent Goalie Mystery

Frankie folded her arms at recess. "Some people say only a few goalkeepers are bossy. I say all great goalkeepers are bossy. They have to shout orders to do the job right. A kid who is perfectly quiet will never be a great goalkeeper." Sharon rolled her eyes. "So what can't happen?" Lulu flipped her clipboard. "Could some kids think every goalie is bossy? Sure, that's just an opinion. Could some bossy goalies be bad? Sure, being bossy doesn't make you great." Tommy asked, "What about a perfectly quiet kid who is a great goalkeeper?" Lulu tapped the page. "That one breaks Frankie's rule. If her statements are true, that kid can't exist."

Step 3 · Try the model question

All great goalkeepers are bossy, because they must shout orders to do the job well. A kid who is perfectly quiet will never be a great goalkeeper.

If Frankie is right, which choice is impossible?

Step 4 · The courtroom tale

The Impossible Witness

Mr. Whitfield read the club rules aloud. "Every champion chess coach keeps a strict timer. Anyone who never uses a timer will never be a champion coach." The witness, Mr. Barlow, leaned into the microphone. "I have never used a timer in my life, and I am a champion coach." The courtroom gasped. Judge Reyes tapped her gavel. "Sir, if the rules are accurate, your statement cannot be true. Some timer users may be poor coaches, fine. But a timer-free champion is ruled out." Mr. Barlow quietly checked his pocket for a stopwatch.

Step 5 · Work the real question

Open PrepTest 103, Section 1, Question 13 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

Diagram each conditional from the author. Combine them if you can. For a CANNOT be true question, four choices will be possible or untouched. Look for the single choice that puts the forbidden pair together: the trait the author says rules out success, plus success itself. Beware choices that reverse an arrow; those can still be true.