LSAT 138 | Section 4 | Logical Reasoning: Q21

LR Question 21 Explanation

QUESTION TEXT: Each of the candidates in this year’s mayoral election…

QUESTION TYPE: Flawed Parallel Reasoning

CONCLUSION: Most mayoral candidates have the skills to be good mayors.

REASONING: Small business owner (most) ➞ Competent manager ➞ Skills to be mayor

Each candidate is a small business owner.

ANALYSIS: There are maybe five candidates for mayor. And 30 million small business owners in America. We know that “most” of those small business owners are competent mangers.

But that still leaves room for, say, 14 million small business owners to be incompetent mangers. The candidates for mayor could be all part of that second group!

Basically, you can’t look at a portion of a group and say that the “most” statement applies evenly to that portion.

To parallel this argument, look for the following structure:

1. A (most) ➞ B ➞ C
2. Every person doing X is an A. So most people doing X are a C.

The answers here are unusually dense. I actually had to try drawing 4 of them. I don’t mean I did draw them. But for A, D and E I started thinking about how to draw them. In that process, I realized that they didn’t match.

Also unusually, at least some of the answers are fairly close structurally. So you have to be quite precise.

___________

1. This answer switches between “management” and “upper management”. In the stimulus, there was no such switch. (Between, say, “small business owners” and “highly successful small business owner”).
2. CORRECT. This matches exactly.
   1. Fat free (most) ➞ sugar free ➞ low in calories.
   2. All items on the menu are fat free. So most of them are low in calories.
3. This conclusion is only about Ed. The stimulus concluded something about most of a group.
   I immediately skipped this answer when I saw the conclusion wasn’t about “most” of something.
   If the conclusion had said “Ed has not read most of his books in less than three hours” then this could have been right.
4. This answer doesn’t try to connect “unsuccessful” to anything in the the conclusion. It should have, since “unsuccessful film” was the original “most” statement. (Matching the role of “most small business owners” in the stimulus)

5. This is a good argument! This argument says, in simpler terms:

   • Rubber ➞ plastic
   • Every helmet in the store has plastic (necessary condition)
   • Most helmets in the store have rubber.

   Conclusion: Most in the store with plastic have rubber.
   This is true! Since all have plastic, and most in the store have rubber, it must be true that most have rubber and plastic.