LR Question 16 Explanation
QUESTION TEXT: At the end of 1997 several nations stated that their…
QUESTION TYPE: Necessary Assumption
CONCLUSION: It’s likely that most countries that say their oil reserves haven’t changed are wrong.
REASONING: A few countries say their reserves haven’t changed last year. But oil reserves are unlikely to stay the same, year on year.
ANALYSIS: Notice the quantity words “several” and “most” in this stimulus. You must always pay attention to quantity words.
Several is perhaps 3-7 countries. And in the whole world, perhaps 100-150 countries have oil reserves. “Likely” might mean 70% of countries will see a change in reserves. So it’s perfectly possible for it to be “unlikely” that oil reserves remain unchanged, and for 3-7 countries to have oil reserves that didn’t change. 3-7 is a small percentage of the total. So the argument has to assume it’s unlikely for this group to have its reserves unchanged.
___________
- Who cares what happens in one country? The negation of an “any” statement is that one country didn’t fit the trend.
Negation: One country is likely to be right that its oil reserves are unchanged. - CORRECT. The conclusion is about “most” countries. If we negate this answer, we no longer have information about most countries that stated their reserves didn’t change.
Negation: It is likely that only half or less of the countries which claimed unchanged reserves had oil fields that were drained or discovered. - We don’t care how reserves change (e.g. slowly or quickly). We only care if they did change.
Negation: In 1997, no single country experienced both a a gradual drop and also a sudden rise in oil reserves. - Who cares what happens in one country?
Negation: One country incorrectly stated its reserves hadn’t changed, but during 1997 it didn’t discover new reserves or drain old ones. - This answer is irrelevant. We care about whether nations are correct, not whether they have an obligation to be correct.
Negation: A nation can experience changes in its oil reserves without having the obligation to report them correctly.
Recap: The question begins with “At the end of 1997 several nations”. It is a Necessary Assumption question. To practice more Necessary Assumption questions, have a look at the LSAT Questions by Type page.
Hello,
I eliminated answer C because it talks about “at least one nation” which is a “some” statement. However, I have learned that you cannot combine a “MOST of the nations are probably incorrect” with a “SOME” statement. Is this a valid method for eliminating the answer choice?
Thank you,
You can’t combine “most” statements with “some” statements when you have a scenario like this:
Premise 1: Most A’s are B’s
Premise 2: Some B’s are C’s
Therefore, some A’s are C’s.
^^That’s an invalid argument. We can’t chain those two premises together to reach that conclusion.
Answer Choice (C) is incorrect for a very different reason, though. It’s not creating an invalid conditional chain. We’re looking for something that’s necessary for the argument of the stimulus, and (C) is suggesting that at least one country is experiencing a very specific scenario with their oil fields. The argument doesn’t need that specific scenario to be true. It requires that at least one country (or most) experienced some kind of change in their oil fields after 1996.
Hi Graeme,
thanks so much for your explanation here. But I had a different understanding of why (A) was wrong – when I see “any”, I thought it means “for any given country”, which means for ALL the countries with oil reserves, it is more likely that … (blah blah). So I thought this was extreme not because it only applied to a single country, but because it applied to ALL countries whereas we just need to satisfy the argument for “most” countries. Please let me know what you think.
Best,
Daina
Also, I think that with this rationale (A) would work as a sufficient assumption, but that it is too broad to be a necessary assumption.
It’s never a problem for something to be “too strong” if it’s working in the right direction. If I want to prove that “most americans aren’t poor” and I provide evidence that “All Americans are millionaires” then I’ve proved the argument. “Too strong” is not a criticism of evidence!
The actual reason is that the negation of an all statement can just be one country, and so the statement could still apply to most countries even when negated.
Also, the logic of the statement doesn’t work. You could have every country with a 60% likelihood of being wrong. But you’d still have 40% of countries being right, if that were true.
So either way the assumption isn’t necessary.
Hi Graeme!
Thanks for your explanation of this LR question. I just want to clarify a few things, both related to the question and also to your reply above.
First: Can you explain to me why we employ the negation technique here? When is that a helpful approach and why? Is it only helpful on NECESSARY assumption questions, and not sufficient assumption questions–or do you use it for both?
Secondly: I selected the correct answer when taking the section for time. I went back to read the explanation just because I am trying to follow your advice about reading explanations on not only questions that you miss, but also ones that slow you down or confuse you, so as to ensure similar questions don’t cause you to lose a point in the future. I was between A and B when taking the section. As I said, my instinct was B, but now I am not so sure how I knew that. Would you mind explaining briefly one more time why B is correct and why A is incorrect?
Lastly: When you replied to Daina saying, “Also, the logic of the statement doesn’t work. You could have every country with a 60% likelihood of being wrong. But you’d still have 40% of countries being right, if that were true.” — I am confused as to why this is pertinent considering the conclusion says “most of the nations stating their oil reserves were unchanged are PROBABLY incorrect.” Isn’t a 60% likelihood of being wrong sufficient to claim they are “probably” incorrect, since it is the majority?
I think I am just confusing myself, but would love to hear your explanation! Thank you so much for your help!
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