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#27557
Complete Question Explanation

Must Be True—SN. The correct answer choice is (E)

This problem is a classic example of how the LSAT attempts to disguise conditional reasoning. The stimulus can be diagrammed as follows:

SF = serious financial problems ..... H = happy

Sentence 1: ..... SF ..... :arrow: ..... H

Sentence 3: ..... H ..... :arrow: ..... SF (solving SF = SF)

The sufficient condition in the first sentence is introduced by the phrase, “people with.” The necessary condition in the third sentence is introduced by the phrase, “only if.” Note that the third sentence provides the contrapositive of the first sentence. The second sentence is not conditional and contains only general statements about the effects of their misery.

The question stem uses the word “inferred” and can be classified as a Must Be True. When you encounter a stimulus that contains conditional reasoning and a Must Be True question stem, immediately look for a contrapositive or a repeat form in the answer choices. In problems with this same combination, avoid Mistaken Reversals and Mistaken Negations as they are attractive but wrong answer traps.

Answer choice (A): One reason answer choice (A) is incorrect is that it only refers to serious problems, not serious financial problems as in the stimulus. Even if the answer correctly referred to serious financial problems, it would still be incorrect because it would be a Mistaken Reversal of the first sentence and a Mistaken Negation of the third sentence.

Answer choice (B): The answer choice can be diagrammed SF ..... :arrow: ..... H.

This answer is incorrect because it is the Mistaken Negation of the first sentence. However, it is also the Mistaken Reversal of the third sentence, which you should recognize as the contrapositive of the first statement. This leads to the interesting point that the Mistaken Negation of a statement and the Mistaken Reversal of the same statement are contrapositives of each other. This fact reveals how important it is to diagram conditional statements correctly; otherwise, the makers of the test can lure you with answer choices which contain contrapositives of Mistaken Negations or Reversals.

Answer choice (C): This answer choice would be diagrammed the same way as answer choice (B), and it is incorrect for the same reasons.

Answer choice (D): The answer choice can be diagrammed as H ..... :arrow: ..... SF.

As such, it is the Mistaken Reversal of the first sentence and also the Mistaken Negation of the third sentence.

Answer choice (E): This is the correct answer chioce. Answer choice (E) is the contrapositive of the first sentence and a repeat of the third sentence.
 haideemaria
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#14490
Hello,

Currently I am working on Must Be True Questions and I wanted a few explanations for wrong answer choices, as the book does not provide any. All of these questions are from the Logical Reasoning Question Type Training book.

pg 25, Q17
This question was also a bit challenging.
My answer: B
Correct answer: E
 Robert Carroll
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#14503
haidee,

This Must Be True question contains conditional reasoning in the stimulus, so it's helpful to diagram the conditional. The stimulus is talking about people with financial problems, but the conditional does not appear until the end: "Only if their financial problems are solved can they and those around them be happy." "Only if" introduces the necessary condition, so "their financial problems are solved" is the necessary condition. The sufficient condition is about people, and so can be phrased "people and those around them are happy". In other words:

people and those around them are happy :arrow: their financial problems are solved

Because the stimulus was talking about people who had financial problems, it makes sense to talk about them being "solved." If someone didn't have a financial problem in the first place, it couldn't be solved. So the conditional tells us that, if someone is happy (and if the people around that person are happy), that person's financial problems, if any existed, were solved.

Moving on to the answers, Answer choice B is the Mistaken Reversal of the conditional. If you diagram the conditional as above, this will become clear.

Answer choice E is correct because it is what the conditional says - either the problems did not exist or they were solved.

Answer choice A brings in new information, so it's not the correct answer.

Answer choice C is another form of Mistaken Reversal.

Answer choice D is a form of Mistaken Negation.
 abifafun
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#20293
Hi,

I need help with identifying why my answer, choice B, for this question is wrong and why choice E is a better answer.

Thank you.
 David Boyle
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#20303
abifafun wrote:Hi,

I need help with identifying why my answer, choice B, for this question is wrong and why choice E is a better answer.

Thank you.
Hello abifafun,

Diagramming "People with serious financial problems are so worried about money that they cannot be happy", we get

sfp :arrow: slash happy.

Answer E says, "If people are happy, they do not have serious financial problems", which is diagrammable as the contrapositive of the above, i.e.,

happy :arrow: slash sfp.

(You can get similar results from diagramming "Only if their financial problems are solved can they and those around them be happy", yielding

happy :arrow: fp solved

, which is similar to happy :arrow: slash sfp.)

Answer B is a mistaken negation of sfp :arrow: slash happy.

Hope this helps,
David
 Mi Kal
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#37157
Hi,

I know for LSAT purposes that "infer" means "must be true." Nevertheless, wouldn't we be looking for an answer that must be true that isn't already in the Stimulus?

It seems to me that E is stated in the Stimulus in the last sentence. So if it is stated, how can it be inferred? Isn't B inferring something that is true that isn't already stated in the passage?

Thanks.

Michael
 Adam Tyson
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#37174
You're right, Michael, that an inference means something that we can deduce from the statements, and most of the time that means it is NOT something the author said. But this test is flawed, sometimes deeply so, and this question is a good example of such a flaw. We aren't inferring that claim - we are just repeating it! So why is that the right answer? Because it is the best answer of the five we were given, and that's what the instructions tell us to select. We didn't infer it, but it is something which, if we accept the claims in the stimulus, must be true, and none of the other answers meets that test.

Why can we not properly infer the claim in answer B? Because it makes a mistaken negation, and while those are possible, they are not provable and should not be inferred. If you're happy you do not have serious financial problems, but if you do not have those problems (whether you had them and solved them or just never had them) you still might not be happy. Marital problems, academic struggles, health problems - all of these could prevent happiness.

E repeats something that we already accepted as true. We didn't need to infer it because it was already spelled our for us. However, of the five answers presented, it is the only one that is supported by the stimulus, and that makes it the best answer of the bunch.

It can be a lousy test sometimes. Sometimes the best answer is just the one that you hate the least. Still, we pick that one and move on without worrying about whether it should have been a better answer. We can complain about it to each other later over a beer after we've crushed the test and HYS are throwing gobs of scholarship money at us. Deal?

Keep up the good work, man! You've got this!
 Mi Kal
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#37209
Hi Adam,

Thanks so much. I appreciate it and if that dream, HYS, actually comes true (although I highly doubt it) we definitely have a deal, but just one beer won't do.

Michael
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 Stephanie Oswalt
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#45996
We recently received the following question from a student. An instructor will respond below. Thanks!
Hi Powerscore staff,

I had a question about question #1 pg. 185 in chapter 6 of Conditional Reasoning (edition 2017). Initially, when I diagrammed the stimulus I missed the first conditional statement because I didn't recognize "people with" as an indicator. I diagrammed the last sentence because I recognized the "only if." I got the question correct but my diagram did not match the book.

My diagram: H --> SFP

H = Happy

SFP = Solved serious financial problems

Is my diagram wrong?

- SA
 Francis O'Rourke
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#46052
That looks like a pretty good diagram of the final statement to me! I am a little worried that you might misinterpret the S in SFP as "serious" instead of "solved". If your acronym is ambiguous, dont' be afraid to clarify it for yourself by adding a full word, for example solvedFP instead of just SFP.

Just remember that phrases that introduce a defined set of people, such as "people who," "anyone that," "people with," will often introduce a sufficient condition.

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