Logical reasoning PrepTest 156 · Section 2 · Question 17

Question prompt

To measure a small Remaining source text redacted.
Why the credited answer is right

Credited answer: D

The notes below walk through why it fits the stem and how to eliminate the rest.

Argument or Facts

Facts

Strategy Overview

Argument or facts in passage?
If argument, identify premises and conclusions
Sufficient/necessary conditions in the passage?
If so, diagram statements and draw any deductions
Use anticipation to find the answer choice that is absolutely 100% true

Answer Anticipation

This set of facts features a few "if-then" keywords, including some "then" keywords ("necessary," "require"). These send us a clear signal that we should diagram these statements to help us draw a conclusion that must be true. The first sentence uses the "then" keyword "necessary." The word "necessary" refers to "level the hull so that a baseline can be established." Let's shorten that to "level hull" and place it on the "then" side. The other part — "measure a small boat hull accurately" — can be shortened to "measure hull accurately" and placed on the "if" side. We'll also find the flipside by flipping the order of the conditions and denying both sides.
P1: Measure hull accurately → Level hull / NOT level hull → NOT measure hull accurately
The next sentence uses the "then" keyword "requires," which refers to "a leveling tool called a 'line level.'" Let's shorten that to "line level" and place it on the "then" side. The other part refers to the action from the previous sentence — leveling the hull. So, we'll place that on the "if" side. Again, we'll take the flipside of this claim.
P1: Measure hull accurately → Level hull / NOT level hull → NOT measure hull accurately P2: Level hull → Line level / NOT line level → NOT level hull
We can connect these two "if-then" statements since the "then" part of one is the same as the "if" part of the other. This connection allows us to draw a conclusion.
P1: Measure hull accurately → Level hull / NOT level hull → NOT measure hull accurately P2: Level hull → Line level / NOT line level → NOT level hull

Answer choices

  1. A
    The scientists did not Remaining source text redacted.
    Why choice A is not credited

    This isn't one of the conclusions we anticipated, so we can cross it off without thinking about it too deeply. Besides, this isn't supported by the passage. Even though the scientists were "not sure" they had leveled the hull, they still could have. If they had, they may have measured the hull accurately. And even if they didn't level the hull or measure accurately, it would not necessarily be because they don't have experience measuring hulls. They could have been careless or not have had access to a line level.

  2. B
    The scientists accurately determined Remaining source text redacted.
    Why choice B is not credited

    This isn't one of our anticipated conclusions, so we can quickly eliminate it. Besides, this isn't supported by the passage. If we diagrammed this claim, it would be "NOT measure hull accurately → NOT line level." (The word "provided" functions like a "trigger," with the outcome being "accurately determined the hull’s dimensions.") That just flips the order of the conditions of the first premise, which is a no-no.

  3. C
    If the scientists did Remaining source text redacted.
    Why choice C is not credited

    This isn't one of the conclusions we anticipated, so let's cross it off. Moreover, this isn't supported by the passage. If we diagrammed this claim, it would be "Level hull → Measure hull accurately." The conclusion we drew from the first two premises is, "Measure hull accurately → Line level." Like (B), this answer choice just flips the order of the conditions, which is not allowed.

  4. D
    The scientists were able Remaining source text redacted.
    Why choice D matches the stem

    This is consistent with the conclusion we drew from the first two premises: "Measure hull accurately → Line level." If we diagrammed this answer choice, we would need to use the "then" keyword "only." The word "only" refers to "used a line level," which we can place on the right side of the arrow. The other part is "measure hull accurately," which will go on the left side of the arrow: "Measure hull accurately → Line level." So, this says pretty much the same thing as the conclusion we drew, but applies that conclusion to the scientists' attempt to measure the hull of the ninth-century boat. The conclusion we drew applies to anyone trying to accurately measure the dimensions of a small boat's hull, so it applies to the scientists. Therefore, this answer choice must be true. We can select it and move on to the next question.

  5. E
    If the scientists had Remaining source text redacted.
    Why choice E is not credited

    This isn't one of our anticipated conclusions, so we can eliminate it without debating its merits. Besides, this isn't supported by the passage. The passage doesn't say or imply that the scientists need experience to measure the hull accurately. They need to level the hull and establish a baseline. And they need to use a line level. But the passage doesn't say they need experience to do these things.

Question analytics

Based on historical answer selection rates for this question.

Answer choice distribution

  1. A 14%
  2. B 14%
  3. C 23%
  4. D Credited 43%
  5. E 6%

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