Logical Reasoning · Flaw

PrepTest 106 · Section 2 · Question 2

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

Step 1 · Pre-Question Guidance · read this first

Question type

Flaw

The one idea it tests

What is true of a team overall is not always true of each player on it.

The basic logic

The argument notes a trait of the group taken as a whole (its main focus). Then it says one individual lacks that trait, so the individual cannot belong. But a group's overall trait need not belong to every member. That is a Team-to-Star Mix-Up.

Tiny words that decide it

“primary”
“so”
“certainly”
“cannot”

Playground logic

The school chess club is mostly about chess, so Marcus says Owen, whose main hobby is drawing, is not in the club. The top bun rests on a Team-to-Star Mix-Up: the club's main focus does not have to be every member's main focus.

Step 2 · The kid story

Detective Marcus and the Chess Club

Marcus pulled out his detective notebook. "Fact one: the Knights Club is the best chess club in the district. They win almost every tournament. Fact two: Owen's main hobby is drawing comics. Conclusion: Owen cannot possibly be in the Knights Club." Priya tilted her head. "The club as a whole is mostly about chess. But does every single member have chess as their number one hobby?" "Well, obviously," said Marcus. Lulu checked her clipboard. "Owen designs the club's posters. He plays chess on Tuesdays. He is a member." Marcus frowned at his notebook. "So the club's main thing is not each kid's main thing?" "Nope," said Priya. "A team can be all about chess while one player's favorite hobby is something else." Biscuit barked once, which seemed to agree.

Step 3 · Try the model question

The Knights Club is the most successful club at school whose main activity is chess. It wins nearly every tournament it enters. Owen's main hobby is drawing comics. So Owen surely is not a member of the Knights Club.

Which of the following best describes the mistake in Marcus's reasoning?

Step 4 · The courtroom tale

The Bakery Guild Mix-Up

A prosecutor pointed at the witness. "The Golden Crust Guild is famous for bread. Its members win nearly every baking prize. This witness mostly makes candles. Therefore she cannot be a guild member, and her guild badge is fake!" Mr. Whitfield rose slowly. "Your Honor, the guild's main craft is bread. That describes the guild as a whole. It does not mean every member's main craft is bread." He held up a list. "The guild includes a candle maker who lights the ovens on festival nights. That is my client." The judge sighed at the prosecutor. "Counselor, you mixed up the team with each player. Badge is real. Next case."

Step 5 · Work the real question

Open PrepTest 106, Section 2, Question 2 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

Spot the trait the argument gives to the whole group. Then spot the individual who lacks it and the conclusion that this person cannot belong. Ask: must every member share the group's overall trait? If not, the flaw is a whole-to-part slide. Choose the answer that describes ruling someone out of a group for lacking a feature that describes the whole team. Skip answers that name flaws, like samples or contradictions, that never happen.