Logical Reasoning · Flaw
PrepTest 106 · Section 3 · Question 2
Phase 1 (your first ~400 questions): read the guidance, then answer. No clock.
Step 1 · Pre-Question Guidance · read this first
- “a number of”
- “no”
- “solely”
Playground logic
Marcus sees that some back-row kids sneaked snacks, so he bans every back-row kid from being snack monitor. The patty is about some kids; the top bun is about all of them. The missing sauce is that those few snack sneakers are typical, and they might just be the odd ones out.
Step 2 · The kid story
The Back Row Snack Ban
Ms. Rivera needed a snack monitor. "It must be someone who has never sneaked a snack," she said. Marcus put on his detective hat. "Easy. A few kids in the back row have sneaked snacks before. Owen once grabbed two cookies. Frankie once took a pretzel. So nobody from the back row can be snack monitor. Case closed!" Nadia raised her hand from the back row. "I have never sneaked anything!" Priya sipped her juice box. "Marcus, you found a few sneaky kids. That does not tell us about all twelve kids back there. Maybe Owen and Frankie are the unusual ones." Lulu wrote on her clipboard: 'Some back-row kids sneaked. Marcus jumped to ALL back-row kids.' Marcus slowly took off his hat. "Maybe I need more clues."
Step 3 · Try the model question
Ms. Rivera wants a snack monitor who has never sneaked a snack. Several kids who sit in the back row have sneaked snacks. Therefore, Marcus says, no kid from the back row should be chosen as snack monitor.
Marcus's reasoning is weakest because it
Step 4 · The courtroom tale
The Red Bicycle Hearing
A town was picking a crossing guard who had never run a stop sign. A lawyer rose. "Your Honor, several people who ride red bicycles have run stop signs. So no red bike rider may be crossing guard!" Mr. Whitfield tugged his suspenders. "How many red bike riders live in town?" "About four hundred." "And how many ran stop signs?" "Three." The courtroom giggled. Mr. Whitfield turned to the judge. "Three riders out of four hundred may be the oddballs, not the rule. My client rides a red bicycle and has stopped at every sign for twenty years." The judge nodded. "A handful of cases cannot paint the whole group. Denied."
Step 5 · Work the real question
Open PrepTest 106, Section 3, Question 2 in your official copy from LSAC (for example in LawHub) and read it there.
Your answer
How to apply it
Find the premise that talks about some people in a crowd, then the conclusion that judges everyone in that crowd. Ask: could those members be unusual? If yes, the flaw is a stretch from a few cases to the whole group. Look for the choice that names a generalization from cases that might not be typical. Skip choices that describe moves the argument never makes (Phantom Pieces).