Logical reasoning PrepTest 130 · Section 4 · Question 9

Correct. Argument or Facts:
Argument

Valid or Flawed:
Valid

Question Type:
Must Be True

Stimulus Summary:
Disease—Affects liver, hard to detect early on, all pythons die within 6 mos of contracting
NA pythons—Some have it
African pythons—A higher proportion have it than NA pythons

Answer Anticipation:
There's a lot of individual information here that doesn't overlap much, but we can tease out a few elements that are more likely to lead to a correct answer. For example, the LSAT frequently uses comparisons to lead to inferences, so that comparison between the rate of the disease in NA pythons and African pythons might play into the correct answer. More likely, that very strong statement at the end will lead to an inference—all pythons die within 6 mos of contracting the disease. We can use that to make inferences about individual pythons, or populations, as long as they are known to have the disease—and we have 2 populations that we know do have some members with the disease. An answer that talks about the North American or African pythons dying within the next 6 mos would be correct.

Answer Explanation:
This answer relies on the strong statement from the stimulus while being weak ("Some"), so we should dig into it more. We do know that some pythons recently hatched in North America have the disease, and they'll be dead within 6 mos, so that part of this answer is supported. Heading back to the stimulus to see if we can support the other part of this answer—that these pythons may appear fine—we see that the stimulus establishes the disease is "difficult to detect" in its early stages, and that wouldn't be true if the pythons didn't appear fine, so we can support this part of the answer, as well. This is the correct answer!

Key Takeaway:
While it can be at times hard to anticipate the specific answer in a Must Be True question, we can generally identify the information in the stimulus that's more likely to lead to a correct answer—comparisons, causal relationships, strong statements. Doing so can make it easier to identify an answer we should dig into and spend more time analyzing.

Incorrect. It is stated that a "much greater proportion" of pythons hatched in Africa have the disease, but that doesn't mean that they're more susceptible to it. It could be that the African pythons are more exposed to the disease, thus explaining why they have a higher rate of contracting it even if they have equal susceptibility.

Incorrect. The stimulus specifically notes that the disease is contracted—it's not something that a python is necessarily born with. If it contracts the disease a few months after birth, it could live past 6 months but still have the disease.

Incorrect. There's no indication that the liver disease is a factor in the pricing—the low prices could be a result of the major shipments increasing supply.

Incorrect. The stimulus is silent on pythons from other areas, so we can't draw an inference about them.