Logical reasoning PrepTest 109 · Section 1 · Question 15

Incorrect. This argument is valid, establishing that Daryl (who is a member of his own family) meets the sufficient condition for being a good runner.

Incorrect. While arguably someone who is a published novelist isn't writing for a living (she might write as a side hustle but make her money as a lawyer), but the premise about Julie meets the sufficient condition of the general rule, so it doesn't feature the same illegal negation as the stimulus.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Flawed Parallel Reasoning

Stimulus Summary:
Good at Drackedary → Skilled with their hands
Mary — Competent watchmaker
Therefore — Mary would be good at Drackedary

Answer Anticipation:
This argument falls into a common pattern—it establishes a general rule/conditional ("invariably") and then it attempts to apply it to a specific situation.

Interestingly this argument in trying to apply the general rule to Mary doesn't bring up any of the concepts in that general rule (in the premise at least). Instead it establishes that she's a competent watchmaker. Looking at the general rule to make sense of this the argument must be assuming that watchmakers are good with their hands. So not only is there a gap between what is established about Mary and what the general rule says but it also at best establishes that Mary meets the necessary condition of the general rule and then it concludes the sufficient condition.

So we need to find and answer that follows the same pattern with the same pair of flaws:
A → B
Example — Something sort of related to B
Therefore — A

Answer Explanation:
This answer follows the same pattern as the stimulus. It establishes a general rule (Race car driver → Good reflexes). It then attempts to apply that rule to Chris but it does so by bringing up something that is related to the conditional without establishing either term. However it does establish that he is a champion table tennis player which is assumed to establish that he has good reflexes—the necessary condition. From this it concludes the sufficient condition. This answer therefore features the same two flaws as the stimulus and is correct.

Key Takeaway:
Make sure you fully analyze the logic in a Flawed Parallel Reasoning question. It's easy to stop after identifying one flaw but many will have a second that also has to match up. It's not the end of the world if you don't but what will happen is that you'll end up with multiple answers that match the flaw you identified and you'll need to spend time to go back to find the other then more time to reanalyze the answers. That's a lot of time that could be better spent elsewhere!

Incorrect. We can throw this answer out after the first line—it establishes what is "often" true which isn't a conditional. Since a conditional logic flaw—an illegal reversal—was present in the stimulus the lack of a conditional means this answer can't be correct.

Incorrect. This answer establishes the sufficient condition of the general rule as the premise, so it doesn't feature an illegal reversal. Instead, it's flawed because it assumes that a conditional relationship establishes a proportional one (Good skier → Learn to skate, so better skiers can learn to skate faster).