Logical reasoning PrepTest 139 · Section 1 · Question 14

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Flawed Parallel Reasoning

Stimulus Summary:
Potential fire causes - Campers and lightning
Investigators haven't proven that it was campers, and they haven't proven it was lightning
Therefore - They haven't proven it was campers or lightning

Answer Anticipation:
"Where's the flaw here?" you might be asking. Fair enough—it's subtle. When you run into a situation like this, try to identify structural elements you can try to match up. Here, the stimulus brings up two options, establishes that neither has been proven, and concludes that it hasn't been proven that either option is correct. With this, you can actually get the correct answer, as only the correct one follows that same pattern.

However, if you want to dig into the flaw, let's take a look. If it hasn't been proven that campers caused the fire, and it hasn't been proven that it was lightning, how can we say the conclusion is flawed?

Well, think about this situation—we fill a bag with nickels and dimes, and no other coins. Someone pulls a coin out and holds it, hidden, in their hand. Can we say for certain it's a dime? Nope. Can we say for certain it's a nickel? Nope. Can we say for certain it's either a dime or a nickel? Yep!

Similarly, the investigators may not be able to establish whether the cause of the fire was campers or lightning, but they may have been able to narrow it down to those two, and thus they may be able to conclude that it was either campers or lightning. Let's find an answer that follows the same pattern or commits the same flaw.

Answer Explanation:
This answer establishes two options, establishes that neither has proof establishing it, and then concludes that there's no proof to establish that one of these two options will come to pass. To bring it back to the flaw, it's possible that Sada and Brown are the only two candidates, so while Kim has no reason to believe that one will win over the other, she does have a reason to believe that one of them will win, and so this is our answer.

Key Takeaway:
When a Flawed Parallel Reasoning question has a flaw that you're having difficulty spotting, identify structural elements that you can mimic. This isn't a perfect method, as not all structural elements will match in every correct answer to this question type, but you can generally narrow it down and identify elements in answers that have no chance of matching up (e.g., the quantifiers here).

Incorrect. The conclusion of this argument is about the two options being equally plausible, which is different from the conclusion of the stimulus.

Incorrect. This answer is an overlapping set/quantifier argument ("Most . . . most"), and so it has a different flaw.

Incorrect. This answer is an overlapping set/quantifier argument ("some . . . some"), and so it has a different flaw.

Incorrect. This answer is about two separate theories being plausible and potentially both correct (which has its own problems here), not that two theories aren't proven.