Logical reasoning PrepTest 144 · Section 4 · Question 14

Incorrect. In limiting itself to "almost" any paper product, this answer doesn't guarantee that this is true of banknotes, and so we can't be sure that it is even relevant let alone a sufficient assumption.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen with Sufficient Premise

Stimulus Summary:
One method of counterfeiting involves measuring elements on a real bill. So if counterfeiting is to be prevented, those things need to be impossible to measure.

Answer Anticipation:
This argument raises a problem—counterfeiting—and an attempted solution to it—making elements of the banknotes impossible to measure.

However, that solution is raised in a conditional conclusion and—interestingly—it's raised as a necessary condition to prevent counterfeits (Prevent high-quality counterfeits → Made difficult/impossible to measure accurately). In other words, solving the problem of counterfeits requires making the measurements impossible to do accurately.

Since this argument is treating the solution as a necessary solution, it's assuming that no other method will work—that the only thing preventing the counterfeiting is this measurement. So we should find an answer that establishes that, since the argument itself doesn't.

Answer Explanation:
This answer establishes that the only thing needed to create a high-quality counterfeit is to have the measurements for the images on the banknote. If that's the case, then preventing counterfeits would require making those elements very difficult/impossible to measure accurately, because once they're measured, a counterfeiter is ready to go. This answer justifies the conclusion, so it's correct.

Key Takeaway:
In general, arguments that bring up a problem and a solution will present the solution as either a sufficient solution ("This will work") or a necessary one ("Only this will work"). Noting the difference is important, as alternative solutions aren't relevant in the first case but are in the second.

Incorrect. This doesn't establish that making these images difficult to measure is a requirement to stop counterfeiting—if anything, it suggests that some type of higher quality printing could also be used to prevent counterfeiters from being able to make replicas.

Incorrect. What countries currently do doesn't speak to what they'd have to do to stop counterfeiting of their currency.

Incorrect. This answer doesn't speak at all to what the new designs entailed or why the counterfeit currency in circulation declined, so it doesn't speak to any necessary means of preventing counterfeiting.