Logical Reasoning · Inference (Must Be True)

PrepTest 116 · Section 3 · Question 11

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

When some succeed without a thing, it is not required; when the thing alone does little without other traits, it is not enough.

The basic logic

Turn each premise into a test. 'Many succeeded without X' removes X as a requirement. 'X alone helps little without these traits' removes X as a guarantee. Use the Lunchbox Rule: the right answer is what the premises force, nothing more, and the Spoiler Test kills anything that could still be false.

Tiny words that decide it

“some”
“alone”
“not required”
“not enough”

Playground logic

Ms. Rivera says many of the best hamster helpers had never owned a pet, and that past pet-owning alone won't help a kid who lacks the key habits. Both patties point at one sealed top bun: having owned a pet is neither required nor enough.

Step 2 · The kid story

The Hamster Helpers

Ms. Rivera picks hamster helpers every month, and Marcus is sure he deserves the job. "I've had three goldfish!" he says. Ms. Rivera smiles. "Some of our very best hamster helpers had never owned a single pet when they started. Owen, for one. Anyone who is patient, organized, and observant can learn the job fast. And honestly, having had pets before won't do much for a helper who is impatient, messy, and never notices anything." Lulu writes it all down on her clipboard. Marcus counts on his fingers. "So my goldfish don't make me a sure thing?" "Nope," says Priya. "And Owen had zero goldfish and was great." Marcus sighs. "Then I'd better start being organized." Mr. Whiskers watches the hamster with great interest and zero patience.

Step 3 · Try the model question

Ms. Rivera: Some of the best hamster helpers had never owned a pet when they started. Anyone who is patient, organized, and observant can learn the job quickly. And having owned pets before does little for a helper missing every one of those habits.

If Ms. Rivera's statements are all true, which of these must also be true?

Step 4 · The courtroom tale

The Case of the Rookie Referee

In a pretend sports tribunal, a league official objects that the new referee never refereed before. Mr. Whitfield calls a witness. "Were several of the league's finest referees first-timers?" "Yes." "And can anyone with sharp eyes, a calm temper, and a good memory for rules learn quickly?" "Yes." "And does years of whistle-blowing help a ref who has none of those?" "Not much." Mr. Whitfield turns to the judge. "Your Honor, then past experience is neither a must nor a guarantee." The judge taps her gavel. "That is all your witness's answers force. I won't say the rookie will be the best ever. But experience alone settles nothing."

Step 5 · Work the real question

Open PrepTest 116, Section 3, Question 11 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

Translate each sentence into a condition. A claim that some succeed without a trait means the trait is not necessary. A claim that the trait alone does little without other qualities means it is not sufficient. Then test each choice with the Spoiler Test: could it be false while every premise stays true? Keep only the choice that cannot. Watch for answers that flip necessary and sufficient or that add comparisons the passage never makes.