Question Type:
Necessary Assumption
Stimulus Breakdown:
Conclusion: If the customer's claim is correct, the store owes her a refund.
Evidence: If the store doesn't process pics properly, the store owes her a refund. The pics were unsatisfactory, despite the fact that the film and the camera were operational and the customer handled the film correctly.
Answer Anticipation:
If the customer's claim is correct, then we can't blame how she handled the film. We can't blame the film or the camera being defective. So are these unsatisfactory pics then clearly the result of the store not processing pictures properly?
I don't know ... are there any other possible ways the pics could have ended up unsatisfactory? Maybe they were processed properly and then the customer spilled some coffee on them on the car ride home from picking them up.
The author seems to be assuming that we've been left with no other hypothesis than that the store botched the processing.
Correct Answer:
B
Answer Choice Analysis:
(A) This is more extreme than anything the author needs to believe. She thinks that "if camera and film and handling of film were all okay, then store owes customer refund".
(B) YES! This looks like our prephrase.
(C) The author doesn't think this camera was defective so no assumptions are being made about defective cameras.
(D) The author is only telling us what would be true if the customer handled the film CORRECTLY (i.e. "if the customer's claim is correct").
(E) The author is only telling us what would be true if the customer's claim WAS correct.
Takeaway/Pattern: This is a fairly common flaw, where an author boxes herself into a conclusion by ruling out what she assumes to be an exhaustive set of scenarios to consider. The correct answer choice models this thinking by saying "The author assumes that if we rule out X, Y, and Z, then it must be W."
#officialexplanation
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- ohthatpatrick
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Atticus Finch
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Q7 - The photographs that the store developed
I narrowed the answers down to B or E and picked E, obviously incorrectly. Any help as to why E is wrong and B is right?
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- nbayar1212
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Elle Woods
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Re: Q7 - why B?
The stimulus tells us that:
1. customer claims to have handled the film correctly.
2. Neither the film nor the camera was defective.
3. If the store does not process the pics properly, then the customer gets a refund.
CONCLUSION: IF the customer's claim is correct, the store owes the customer a refund.
Do you see the gap between the conclusion and the third premise? IF not, it might become more clear after seeing it in conditional form:
P: If ~process correctly ----> Refund
C: Customer correct ---> Refund
The gap is that we have no link between the sufficient condition of the conclusion and the sufficient condition of the premise. We need an AC that connects these two with something like "If customer correct ---> pics ~process correctly". Notice that if we add this above, we have a nice logical chain that allows us to conclude the conclusion.
In more simplified terms, we have a situation where a conditional says if X happens, then Y should happen and then in the conclusion we now have a claim that indicates Y should happen... but did X happen? We don't know! Thats the assumption!
B gets at this gap by pointing out that if neither the film nor the camera was defective, and the customer handled the film correctly, then the store processed it improperly.
^^ Notice that the last part of this AC gives us the sufficient condition for the last premise in the stimulus i.e. what would happen if the store processes the pictures improperly. Since we meet the sufficient condition now, we can conclude that X (which in this case corresponds to the customer getting a refund) should happen.
E is wrong because it is a mistaken inference. The conclusion says that if the customers claim is correct, then the store owes her a refund. E then turns around and says if the customer's claim is not correct then the store does not owe her a refund. This is an inverse fallacy.
Here is a brief lesson in logic:
If A ---> B, the only thing we know for sure is that if we don't have B, then we don't have A i.e. ~B ---->~A.
Two common mistakes are :
1. Thinking that if you have B then you have A i.e. (B ----> A)
2. Not having A means that you don't have B (~A ----> ~B).
Answer choice E makes the second of the two above mistakes which is why its wrong.
Hope this helps.
1. customer claims to have handled the film correctly.
2. Neither the film nor the camera was defective.
3. If the store does not process the pics properly, then the customer gets a refund.
CONCLUSION: IF the customer's claim is correct, the store owes the customer a refund.
Do you see the gap between the conclusion and the third premise? IF not, it might become more clear after seeing it in conditional form:
P: If ~process correctly ----> Refund
C: Customer correct ---> Refund
The gap is that we have no link between the sufficient condition of the conclusion and the sufficient condition of the premise. We need an AC that connects these two with something like "If customer correct ---> pics ~process correctly". Notice that if we add this above, we have a nice logical chain that allows us to conclude the conclusion.
In more simplified terms, we have a situation where a conditional says if X happens, then Y should happen and then in the conclusion we now have a claim that indicates Y should happen... but did X happen? We don't know! Thats the assumption!
B gets at this gap by pointing out that if neither the film nor the camera was defective, and the customer handled the film correctly, then the store processed it improperly.
^^ Notice that the last part of this AC gives us the sufficient condition for the last premise in the stimulus i.e. what would happen if the store processes the pictures improperly. Since we meet the sufficient condition now, we can conclude that X (which in this case corresponds to the customer getting a refund) should happen.
E is wrong because it is a mistaken inference. The conclusion says that if the customers claim is correct, then the store owes her a refund. E then turns around and says if the customer's claim is not correct then the store does not owe her a refund. This is an inverse fallacy.
Here is a brief lesson in logic:
If A ---> B, the only thing we know for sure is that if we don't have B, then we don't have A i.e. ~B ---->~A.
Two common mistakes are :
1. Thinking that if you have B then you have A i.e. (B ----> A)
2. Not having A means that you don't have B (~A ----> ~B).
Answer choice E makes the second of the two above mistakes which is why its wrong.
Hope this helps.
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- WaltGrace1983
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Atticus Finch
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Re: Q7 - why B?
I've got a little bit more analysis to add if you don't mind!
This is one of the strangest NA questions I have ever seen because it functions exactly like the typical SA question, with a long strand of conditionals and such.
This is a necessary assumption question but one thing to really keep in mind is that we are not trying to absolutely 100% prove the conclusion. Instead, we are trying to find what is necessary to make the conclusion follow from the premises. Our main premise is that ~(Process Pictures Properly) → Refund. Thus, how do we show that, if the (Claim is Correct), then Refund? Because we are only given one way (or one sufficient condition) for a refund to be brought about, we must assume that there is a connection between (Claim is Correct) and ~(Process Pictures Properly). In other words, we must assume that ~(Process Pictures Properly).
(B) gives us this and even goes one step further by actually giving us a sufficient assumption. If (B) is true, then the conclusion must absolutely 100% follow - no if's and's or but's.
(A), (C), (D), and (E) are all false inferences, stuff that we cannot infer from the given stimulus.
If you are new to NA questions, this one is super weird FYI
This is one of the strangest NA questions I have ever seen because it functions exactly like the typical SA question, with a long strand of conditionals and such.
- (Handled Film Correctly) & ~(Defective Film) & ~(Defective Camera)
+
~(Process Pictures Properly) → Refund
→
Claim is Correct → Refund
This is a necessary assumption question but one thing to really keep in mind is that we are not trying to absolutely 100% prove the conclusion. Instead, we are trying to find what is necessary to make the conclusion follow from the premises. Our main premise is that ~(Process Pictures Properly) → Refund. Thus, how do we show that, if the (Claim is Correct), then Refund? Because we are only given one way (or one sufficient condition) for a refund to be brought about, we must assume that there is a connection between (Claim is Correct) and ~(Process Pictures Properly). In other words, we must assume that ~(Process Pictures Properly).
(B) gives us this and even goes one step further by actually giving us a sufficient assumption. If (B) is true, then the conclusion must absolutely 100% follow - no if's and's or but's.
(A), (C), (D), and (E) are all false inferences, stuff that we cannot infer from the given stimulus.
- (A) Refund → ~(Defective Camera) & ~(Defective Film)
This is mistaken reversal. We know nothing if (Refund) is a sufficient condition.
(C) (Defective Camera) → ~(Process Pictures Properly).
This is also an invalid inference. We only know something about ~(Process Pictures Properly) when it is a necessary condition.
(D) ~(Handled Film Correctly) → (Photos Unsatisfactory)
We don't care (nor do we know) if ~(Handled Film Correctly) caused anything. That is completely unsupported.
(E) ~(Claim Correct) → ~(Refund)
This is a false negation of Claim is Correct → Refund, which is invalid.
If you are new to NA questions, this one is super weird FYI
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- erikwoodward10
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Elle Woods
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Re: Q7 - why B?
Interesting to see that a SA answer choice could be the correct answer for a NA question stem. Logically it makes sense. I wonder though if the LSAT would ever put a NA answer choice in a SA question stem, especially as an incorrect answer? That would be pretty evil, just wondering if it is something worth looking out for.
Ill also add a few comments about the answer choices:
A) this starts with the conclusion as the SC, and we can eliminate it right off the bat. Like in an SA question, we need to arrive at the conclusion. Assuming the conclusion to be true won't help us, we need to conclude its validity.
D) This doesn't describes the opposite of what happens in the conclusion, so immediately I think to my self that the only way this could be correct is if we take the contrapositive. While the contrapositive would then match up with the stimulus (and could be applied, as we have a valid condition to work off of), it really doesn't take us anywhere.
E) Same as E. Take the contrapositive, that gives us refund-->correct. Not helpful, this doesnt have to be true. Maybe the store owes the customer a refund for another reason--they spilled coffee on her pictures.
Ill also add a few comments about the answer choices:
A) this starts with the conclusion as the SC, and we can eliminate it right off the bat. Like in an SA question, we need to arrive at the conclusion. Assuming the conclusion to be true won't help us, we need to conclude its validity.
D) This doesn't describes the opposite of what happens in the conclusion, so immediately I think to my self that the only way this could be correct is if we take the contrapositive. While the contrapositive would then match up with the stimulus (and could be applied, as we have a valid condition to work off of), it really doesn't take us anywhere.
E) Same as E. Take the contrapositive, that gives us refund-->correct. Not helpful, this doesnt have to be true. Maybe the store owes the customer a refund for another reason--they spilled coffee on her pictures.
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