Logical reasoning PrepTest 134 · Section 2 · Question 3

Correct. Argument or Facts:
Argument

Valid or Flawed:
Valid

Question Type:
Parallel Reasoning

Stimulus Summary:
Joe's car vacuumed → K&L vacuum Joe's car
K&L vacuum Joe's car → Joe took it to be fixed
Joe's car vacuumed
Therefore — Joe took his car to be fixed

Answer Anticipation:
Conditional logic—based Parallel Reasoning questions need to have answers that follow the same conditional pattern, so we should make sure our diagram is accurate, and then create an abstract version of it so that we can compare the answers to it.

Let's start by making sure we have the diagram correct. The first clause uses "Whenever" to introduce the conditional—that's the same as "If," so it's the sufficient condition. The second clause (after the semicolon) repeats that clause (if K&L is the only place Joe's car is vacuumed, then if it was vacuumed, he took it there). Repeated clauses aren't logically relevant, so we can discount that.

From there, the argument introduces as straightforward a conditional as you'll get on the exam ("If. . . then. . . "). Then, it presents a nonconditional premise that triggers the first conditional, and it concludes the necessary condition of the second conditional.

Since the conditionals can be validly chained together, this argument is valid, an application of a conditional statement to a specific case. Note that it'll likely be important that there is a nonconditional premise that allows a nonconditional conclusion to be drawn. Don't confuse those last two clauses as a single conditional statement, as they're separate sentences, and there's a "Therefore" between them.

Let's take the diagram we have and make an abstract version of it, noting the terms that overlap:
A → B
B → C
A
Therefore — C

Let's find an answer that matches.

Answer Explanation:
Water glass wet*
Water glass wet → Drinks water in morning
Drinks water in morning → Takes her medication
Therefore — Emily took her medication this morning
*Be careful to not eliminate this answer since the first statement isn't conditional! The order that everything is presented doesn't have to be parallel, just the connections. This statement matches up with the last premise in the stimulus, so it could still be correct at that point. And with all statements diagrammed, we can see that this has two conditionals that chain together, a nonconditional that triggers the sufficient condition, and a conclusion that's the necessary condition of the chain. Therefore, this is the correct answer.

Key Takeaway:
Don't just look for elements that were in the stimulus when analyzing answers with conditional logic—also look for elements in the answer that weren't in the stimulus to make eliminations.

Incorrect. This argument features an either/or statement that isn't present in the stimulus, so we can rule it out without diagramming it.

Incorrect. The conclusion here features a brand new term— "someone else"—so it's not parallel. (It's also flawed—there's nothing to say that John didn't place his bills on the kitchen table and then move them later.)

Incorrect. This is an unbelievably tempting answer choice, but it can be eliminated without even diagramming it. How? Because the conclusion is conditional, and there's no nonconditional premise. In both of those ways, this answer isn't parallel to the stimulus. Additionally, if you do diagram it out, it features an illegal reversal so, unlike the stimulus, it's invalid.

Incorrect. This argument features an either/or statement that isn't present in the stimulus, so we can rule it out without diagramming it.