Whoever murdered Jansen was undoubtedly in Jansen’s office on the day

Question

Whoever murdered Jansen was undoubtedly in Jansen’s office on the day of the murder, and both Samantha and Herbert were in Jansen’s office on that day. If Herbert had committed the murder, the police would have found either his fingerprints or his footprints at the scene of the crime. But if Samantha was the murderer, she would have avoided leaving behind footprints or fingerprints. The police found fingerprints but no footprints at the scene of the crime. Since the fingerprints were not Herbert’s, he is not the murderer. Thus Samantha must be the killer.

Which one of the following, if assumed, allows the conclusion that Samantha was the killer to be properly inferred?

(C) No one but Herbert and Samantha was in Jansen’s office on the day of the murder.
(D) The fingerprints found at the scene of the crime were not Jansen’s.

Which one of the following, if assumed, allows the conclusion that Samantha was the killer to be properly inferred?

(A) If there had been footprints at the scene of the crime, the police would have found them. 
(B) Jansen’s office was the scene of the crime.
(C) No one but Herbert and Samantha was in Jansen’s office on the day of the murder.
(D) The fingerprints found at the scene of the crime were not Jansen’s.
(E) The fingerprints found at the scene of the crime were not Samantha’s.

Bunuel · Accepted Answer

EXPLANATION FROM Fox LSAT

The conclusion is, “Samantha must be the killer.” The question asks us to make that conclusion “properly inferred.” In other words, we’re the prosecution. We’re going to try to give Samantha the electric chair. What piece of evidence will  prove  that Samantha is the killer? The evidence we already have is as follows: 
Samantha was in Jansen’s office. So was Herbert, but he is purely a distraction. If Herbert had committed the murder, the police would have found his fingerprints or his footprints. But the police found no footprints at all, and the fingerprints they found weren’t Herbert’s. So we know, already, that Herbert isn’t the killer. But does that prove it’s Samantha?

If Samantha was the killer, she would have avoided leaving any fingerprints. The police did find fingerprints. But they might not be Samantha’s, so she could still be the killer. Our evidence is  very  weak here. Other than Samantha being in the office, we have no evidence that ties her to the murder. If the fingerprints are hers, then she is  not  the killer. And if the fingerprints are not hers, that hardly proves she did it.

What would prove she did it? Well, it’s going to have to be something like, “Nobody else could have done it besides Samantha and Herbert.” If that’s true, and we know Herbert didn’t do it, then it  must  be Samantha.

A) Samantha wouldn’t have left footprints if she was the killer. But the fact that she did  not  leave footprints hardly implicates her. So the fact that the police would have found them if they were there does absolutely nothing to point to Samantha as the killer.

B) It really doesn’t help us that the office was the scene of the crime, because we already know that whoever did it was in the office at some time that day, and Herbert and Samantha are among those people. Millions of other people could have been there as well. This ain’t the answer.

C) Ahh. If this is true, then Samantha is the only remaining candidate because Herbert is not the killer, only Herbert and Samantha were in the office that day, and whoever murdered Jansen was in his office that day. If this is true, I don’t see how it’s possible that Samantha is not the killer. That’s the kind of certainty we want, if we want to fry her.

D) Who cares? The fingerprints could belong to anyone. If they’re Samantha’s, then she is  not  the murderer. If they are someone else’s, then maybe they are the murderer.

E) Samantha wouldn’t have left fingerprints if she was the killer. But the fact that she did  not  leave fingerprints doesn’t point to her guilt.

Our answer is C.

CrackverbalGMAT · Answer

The right answer should be  C . The real toss up here is between options C and D, so let's get into that.

D  - This tells us that the fingerprints were not Jansen's. But that just means it could be anyone's. It could be someone not mentioned here. If so, that doesn't help the conclusion that it was Samantha's.

C  - If only these 2 were in the office on the day of the murder, then it excludes the possibility that it could be some unnamed person. Hence, it becomes more likely that it was Samantha then.

The statement in the argument that clinches it is this: " and both Samantha and Herbert were in Jansen’s office on that day ". Note that it just says "both" and not "ONLY". We know these two were in the office, but anyone else could have been as well. We need to find something therefore that addresses that idea.

- Matoo

MikeScarn · Answer

Nice Question!

I think the  PowerScore Complete Explanation  that  Akela  posted certainly explains the question completely.

I'll still add my two cents on (C) and (D).

This is an   Assumption   question, so we can use the   negation technique   in our POE.

Let's negate (D)

Tempting eh!? If we negate this one, then that surely seems to wreck our conclusion right?

Well, not necessarily. We want to conclude that Samantha was the killer, but we already know that  Samantha  would not have left fingerprints or footprints.

So, are we even concerned with fingerprints at this point? As long as they are not Herbert's (because if it was him, his fingerprints would have been found) then we can conclude that the murderer is Samantha - given the information that we have.

So Negating (D), although it looks tempting,  does not  wreck our conclusion.

Now let's negate (C)

Now this is doing some real damage. Our conclusion relies on the premises that Herbert would have left finger/foot prints, but the prints that were found were not his, so it must have been Samantha.

But this negated answer choice brings in some  damaging  information. There was  someone else  at the scene of the crime (Jansen's office)!  That wrecks our conclusion , it could have been someone else other than Samantha!

Hope this helps.

Bunuel · Answer

EXPLANATION FROM POWER PREP

This stimulus provides something of a murder mystery. Jansen’s murderer was in the victim’s office on the day of the crime, and Samantha and Herbert were both in Jansen’s office on that day. Had Herbert committed the crime, the police would have found his fingerprints or footprints at the scene. Had Samantha committed the crime, she would have avoided leaving behind any fingerprints or footprints. Fingerprints were found at the scene, but there were no footprints. The fingerprints did not belong to Herbert, so it makes sense to conclude that he is not the murderer. Once Herbert has been ruled out as a suspect, however, the writer jumps to the conclusion that Samantha must have been the culprit. This argument has many premises, breaking down as follows:

Premise: Jansen’s murderer was in Jansen’s office the day of the crime.

Premise: Samantha and Herbert were both in Jansen’s office that day.

Premise: If Herbert were the culprit, he would have left prints.

Premise: If Samantha were the culprit, she’d have avoided leaving prints.

Premise: The police found fingerprints, but no footprints.

Premise: The fingerprints were not Herbert’s.

Subsidiary
Conclusion: Therefore, Herbert is not the murderer.

Conclusion: Therefore, Samantha must be the killer.

This conclusion is not fully justified based on the information provided. It is  possible  that Samantha is the killer, because we only know that she would have  avoided  leaving prints, so the prints found at the scene could have belonged to her. However, this argument is not air-tight, because only two possible suspects have been identified. Could there have been another culprit entirely? There simply is not enough information to justifiably conclude that Samantha was the only conceivable murderer.

The question stem asks which of the answer choices allows the conclusion in the stimulus to be properly drawn. The correct answer choice will allow the reader to justifiably rule out  all  other possible suspects.

Answer choice (A): Since Herbert has already been ruled out, this answer choice merely lends support to the assertion that Herbert could not have been the culprit.

Answer choice (B): We were told in the stimulus that the murderer was in Jansen’s office on the day the crime took place, so this answer choice provides no additional relevant information to help justify the conclusion that it must have been Samantha.

Answer choice (C):  This is the correct answer choice. If all other possible culprits have been eliminated (since the murderer was in the office that day, and Herbert and Samantha were the only ones in the office on the day of the crime), then we can justifiably conclude that the only remaining possible offender would have been Samantha.

Answer choice (D): The stimulus describes the death as a murder, so we already know that the culprit must have been someone other than Jansen. This answer choice, therefore, offers no relevant information to justify the conclusion about Samantha.

Answer choice (E): If the fingerprints found at the scene did not belong to Samantha, this obviously weakens the conclusion that she was the culprit, so this answer choice does not provide an assumption on which the argument depends.

unraveled · Answer

Whoever murdered Jansen was undoubtedly in Jansen’s office on the day of the murder, and both Samantha and Herbert were in Jansen’s office on that day. If Herbert had committed the murder, the police would have found either his fingerprints or his footprints at the scene of the crime. But if Samantha was the murderer, she would have avoided leaving behind footprints or fingerprints. The police found fingerprints but no footprints at the scene of the crime. Since the fingerprints were not Herbert’s, he is not the murderer. Thus Samantha must be the killer.

Which one of the following, if assumed, allows the conclusion that Samantha was the killer to be properly inferred?

(C) No one but Herbert and Samantha was in Jansen’s office on the day of the murder.
(D) The fingerprints found at the scene of the crime were not Jansen’s.

Which one of the following, if assumed, allows the conclusion that Samantha was the killer to be properly inferred?

(A) If there  had been footprints at the scene of the crime , the police would have found them. - WRONG. THen what !! It doesn't impact the conclusion. 
(B) Jansen’s office  was the scene of the crime . - WRONG. Reiterates what's already there in the passage.
(C)  No one but Herbert and Samantha was in Jansen’s office  on the day of the murder. - CORRECT. If there had been a third person then Samatha has a chance of being not the murderer.
(D) The  fingerprints found  at the scene of the crime  were not Jansen’s.  - WRONG. Police already would have found it. 
(E) The  fingerprints found  at the scene of the crime  were not Samantha’s . - WRONG. Goes against the passage's conclusion.

Answer C.

VerbalBot · Answer

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Whoever murdered Jansen was undoubtedly in Jansen’s office on the day

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