Unplugged Practice Test: Logical Reasoning Set 3, Question 17 (Weaken)
Taking the test? Finish it first. This page shows the answer.
- Weaken questions ask which new fact most undermines the argument.
- Find the gap the argument leaves open, then look for the choice that widens it.
- 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
Ferreira: Nearly every loss a shop takes on bad currency comes from a cashier accepting a counterfeit note, and counterfeits do circulate among the 50s in this city. Even so, the notices urging every downtown shop to stop taking 50s have little to recommend them. Cashiers seldom accept a note they have any doubt about, and the overwhelming share of 50s in circulation are genuine.
17. Which one of the following, if true, most weakens Ferreira's argument?
- (A)Counterfeit 50s seldom travel beyond the downtown blocks, and they are close enough copies that a cashier has no doubt about them.
- (B)A counterfeit 50 has a far greater chance of being handed on to another shop than to reach any other kind of business.
- (C)Most counterfeit notes made anywhere in the country are of denominations that a downtown shop rarely takes in.
- (D)The counterfeits turned out by the most prolific forgers are not the ones that circulate downtown.
- (E)Downtown shops go through their receipts more closely than shops elsewhere in the city do, so the counterfeits that get recorded are mostly downtown ones.
AWhy (A) is correct
Ferreira grants that nearly every loss a shop takes on bad currency comes from a cashier accepting a counterfeit note, then argues the notices urging downtown shops to stop taking 50s aren't worth much, because cashiers seldom accept a note they doubt and the overwhelming share of 50s in circulation are genuine. (A) undercuts that reassurance: if counterfeit 50s stay concentrated downtown and copy the real thing closely enough that a cashier has no doubt about them, the very carefulness Ferreira cites won't stop cashiers there from taking them, and downtown shops face a real risk the citywide averages hide.
Why the other answers are wrong
BWhy (B) is wrong
(B) says a counterfeit 50 is more likely handed on to another shop than to reach any other kind of business, which says nothing about whether downtown cashiers can spot one.
CWhy (C) is wrong
(C) says most counterfeits made anywhere are denominations downtown shops rarely take in, which would ease Ferreira's worry rather than deepen it.
DWhy (D) is wrong
(D) puts the counterfeits from the most prolific forgers outside downtown, which again points away from downtown risk, supporting Ferreira instead of weakening him.
EWhy (E) is wrong
(E) explains why downtown counterfeits get recorded more often, closer bookkeeping, but that's about detection after the fact, not about whether cashiers can tell a counterfeit 50 from a real one before accepting it.
Common questions
What type of question is this?
Weaken. Weaken questions ask which new fact most undermines the argument.
How do I get better at Weaken questions?
Find the gap the argument leaves open, then look for the choice that widens it. The free LSAT cheat sheet lists the wrong-answer patterns to watch for on every type.
