Unplugged Practice Test: Logical Reasoning Set 1, Question 9 (Flaw)
Taking the test? Finish it first. This page shows the answer.
- Flaw questions ask you to name the reasoning error the argument commits, not to judge whether its conclusion is true.
- Before you read the choices, describe the argument's error in your own words. Most Flaw questions reward 1 of a small set of recurring patterns, so naming the pattern first keeps the trap answers from sounding right.
- Every question on this test is original, written to the same logical skeletons as real questions, and Steve checked every one himself before release.
The question
Fenwick: Ostrander reports that her study shows the single best step available to a borrower carrying a high-interest card balance is to stop using the card until that balance is paid off. Her conclusion is plainly mistaken. A legal ceiling on the rates lenders may charge would shrink those balances far faster than any borrower's own restraint could, as the arithmetic of compounding makes obvious.
9. Fenwick's reasoning is questionable in that it
- (A)dismisses a position by faulting the person who advanced it instead of the evidence behind it
- (B)presupposes without argument that no one other than borrowers with high-interest balances has reason to curb card use
- (C)concludes that a step benefits a whole population from evidence that it benefits particular people within that population
- (D)assumes that a ceiling on rates would help borrowers, though that very point is what the exchange is about
- (E)answers advice about what an individual borrower should do as though it were a proposal about how lending ought to be regulated
EWhy (E) is correct
Ostrander's advice is aimed at one kind of person: a borrower stuck with a high-interest balance, told to stop swiping the card until it's paid off. Fenwick's rebuttal talks about something else entirely, a legal cap on the rates lenders can charge, which is a question of regulation, not personal financial behavior. He never actually rebuts the advice Ostrander gave; he substitutes a policy debate for it and declares the policy answer better. That swap, treating individual guidance as a regulatory proposal, is the flaw.
Why the other answers are wrong
AWhy (A) is wrong
(A) Fenwick doesn't reject Ostrander's point by attacking her; he engages with a claim, just the wrong one.
BWhy (B) is wrong
(B) Nothing in Fenwick's argument requires assuming only high-interest-balance borrowers have reason to cut back on card use; his response doesn't turn on that.
CWhy (C) is wrong
(C) There's no move from some borrowers to all borrowers here; Fenwick isn't generalizing from part of a group to the whole group.
DWhy (D) is wrong
(D) Whether a rate ceiling would actually help borrowers isn't a hidden premise Fenwick sneaks past the reader; it's not what the disagreement is about.
Common questions
What type of question is this?
Flaw. Flaw questions ask you to name the reasoning error the argument commits, not to judge whether its conclusion is true.
How do I get better at Flaw questions?
Before you read the choices, describe the argument's error in your own words. Most Flaw questions reward 1 of a small set of recurring patterns, so naming the pattern first keeps the trap answers from sounding right. The free LSAT cheat sheet lists the wrong-answer patterns to watch for on every type.
