Logical reasoning PrepTest 126 · Section 1 · Question 4

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen with Sufficient Premise

Stimulus Summary:
Delta vacuums with equivalent motors have dust filters of varying efficiency, so power isn't enough to predict cleaning effectiveness.

Answer Anticipation:
Another way of phrasing this conclusion? There are factors influencing how effectively a Delta vacuum can clean other than the power of the motor. In order to justify that conclusion, it would have to be shown that either 1) two vacuums of equivalent power don't clean equally, or 2) there's another factor related to cleaning effectiveness.

The premise here doesn't do a trial run of cleaning effectiveness, instead focusing on another element of Delta vacuums—the dust filters. Therefore, the argument is assuming that the dust filters also influence cleaning effectiveness.

Answer Explanation:
This answer establishes another factor outside of engine power determining cleaning effectiveness of Delta vacuums. If this is the case, and dust filters vary even in vacuums with the same power of motor, then that power wouldn't be enough to predict cleaning effectiveness.

Key Takeaway:
LSAT conclusions will sometimes be phrased in an intentionally obtuse manner to distract you from what it's actually saying. Here, saying that one thing doesn't allow an accurate prediction to be made is a more complicated way of saying it's not the only factor. Always paraphrase these ideas into a more straightforward manner when possible!

Incorrect. This is a very tempting answer. However, the conclusion states that you can't predict cleaning effectiveness based on motor power. If there's another factor that allows an accurate prediction to be made, that doesn't guarantee that motor power couldn't also allow such a prediction to be made.

Incorrect. If anything, this answer aligns with the opposite conclusion, that motor power does equate to cleaning effectiveness. That said, because this answer is a reversal of that relationship, it doesn't actually allow that conclusion to be drawn.

Incorrect. This answer still aligns with the idea that motor power can predict cleaning efficiency—if motor power always determines cleaning efficiency, then that would apply to models with equivalent dust filters. As such, it doesn't guarantee that there's another factor in determining cleaning efficiency.

Incorrect. Establishing motor power as a necessary factor in cleaning efficiency doesn't justify—or even help to justify—that there are other factors besides motor power that are relevant.