PrepTest 140

Incorrect. The stimulus is about certain nations in a given year, so this answer is too broad in talking about "any nation" at any time. Additionally, the argument doesn't need it to be more likely that they were wrong—it needs them to be wrong.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen with Necessary Premise

Stimulus Summary:
1997: Several nations say their oil reserves hadn't changed over the past year.
Oil reserves: Drop as oil is drilled and increase as oil is found
Intermediate conclusion: Oil reserves are unlikely to stay the same year to yearMain Point: Most of these nations are wrong. (i.e., The oil reserves changed in most of these countries.)

Answer Anticipation:
The argument draws a conclusion about "several nations," but it's premise is about what is unlikely to be true of a nation's oil reserves. The logical force there only covers 50+% of the time, not 100%, so there's room for a few nations to fall into the unlikely scenario where the oil reserves do remain unchanged from year to year. In order for the argument to work, therefore, it must be assumed that the changes noted in oil reserves did happen in these countries, thus meaning their statements were incorrect.

Answer Explanation:
This answer specifically limits itself to discussing the given nations in 1997, so it's very specific to the argument—a good thing for a Strengthen with Necessary Premise questions. If, in most of these nations, oil fields weren't drained and oil fields weren't discovered, then the argument falls apart—these countries very well may be correct in stating their oil reserves didn't change. The argument relies on these nations' oil reserves changing from either discovering new oil or using up old oil, so this answer is correct.

Key Takeaway:
When a conclusion states that someone was "incorrect," rephrase that to be a positive statement of the author's conclusion. It can make it a lot easier to juggle the two viewpoints!

Incorrect. There doesn't need to be a nation that had an up-and-down year for the argument to work—just at least one nation that either went down or up.

Incorrect. This answer reverses the stimulus, establishing a nation being wrong as a sufficient condition, which doesn't align with reaching that determination in the conclusion. Note that if this answer stating a nation being correct about its oil reserves was a sufficient condition, then we'd have to consider it (since the contrapositive would establish the nation being incorrect as the necessary condition).

Incorrect. Any obligation to report oil reserves correctly is out of scope in this argument that's just about whether they did report correctly. If the conclusion added on something like, "thus violating international agreements," then we'd have to consider this answer.