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#36392
Complete Question Explanation

Assumption. The correct answer choice is (E)

The argument in the stimulus appears as follows:

..... Premise: ..... Although we could replace the beautiful—but dilapidated—old bridge across
..... ..... ..... ..... Black River with a concrete skyway,

..... Conclusion: ..... we should instead replace it with a cable bridge

..... Premise: ..... even though this would be more expensive than building a concrete skyway.

..... Premise: ..... The extra cost is clearly justifi ed by the importance of maintaining the beauty
..... ..... ..... ..... of our river crossing.

Since you are asked to identify an assumption on which the argument depends, you must look for
any leaps in the reasoning (Supporters), or any ideas that threaten the stimulus that must be rejected
(Defenders).

As in any Assumption question, consider the conclusion: we should replace the old bridge with a
cable bridge. Why is that the case? The author states that we must do so despite the expense in order
to maintain the beauty of the river crossing (this reasoning is extremely questionable because it fails
to consider that a properly designed concrete skyway might be just as beautiful as a cable bridge).
Most students, when examining this stimulus, see that connection and realize that the author has
assumed that the cable bridge will be more attractive. Using that prephrase, they are then able to
effectively dispose of this question by accelerating through this problem and selecting (E).

If you did not see that connection after reading the stimulus, do not forget to use the Assumption
Negation Technique, which can help confi rm that you have selected the correct answer.

Answer choice (A): The author does not see cost as a major issue, so the author is not committed to
the idea that the cable bridge is not more costly to maintain.

If you are unconvinced, negate the answer, and consider how the author would respond to the
negation. Even if the cable bridge were more expensive to maintain, the author of this argument
might still insist that the beauty is worth the cost, so this response is not critical to the argument.

Answer choice (B): The argument cannot depend on an assumption that is contradictory to the
argument’s premises (cost advantage is most certainly a practical advantage), so this response is
defi nitely wrong. Furthermore, even allowing for some leeway with this response, the author might
not care about practical concerns.

Answer choice (C): This is the most attractive incorrect answer. However, “beauty” in this stimulus
is only tied to a concept the author wishes to maintain, and the author is not tied to a specifi c level
of beauty. For example, preservation implies a reasonably equal level of beauty, and technically the
author’s argument allows for the possibility that preservation of the site’s current level of beauty is
not essential. The author could accept some lower standard of beauty, and therefore still choose to
advocate a more beautiful bridge.

From an Assumption Negation Technique standpoint, the correct negation of this answer is: “The
beauty of the river crossing does not necessarily need to be preserved.” In response to this negation,
the author could note that while it doesn’t need to be preserved, there are still benefi ts to having
some level of beauty present, and that therefore the cable bridge is still the preferred choice.

Answer choice (D): This answer choice trades on how people would react to the cable bridge,
but popular opinion is not a good method of proof or disproof on the LSAT. Even if most people
believed the money poorly spent, the money could still be well spent. Also, people could simply have
no particular opinion at all, and that would not damage the argument. In the realm of argumentation,
opinions mean little and prove less. Search for an answer with a basis in fact.

Answer choice (E): This is the correct answer choice. If you are uncertain as to whether this
answer is correct, use the Assumption Negation Technique. If the cable bridge is not more beautiful
than the concrete bridge, how is the author’s argument affected? Because beauty was a driving factor
in advocating a cable bridge, the negation of this answer choice would severely weaken the author’s
argument, and hence this answer is correct.

Mechanistically, notice that “beauty” appears in one of the premises and nowhere else, and “cable
bridge” appears in the conclusion but nowhere else. Not surprisingly, these ideas are linked in this
assumption of the argument.
 silent7706
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#67195
Hi,

Unfortunately I got this one wrong by picking (C). For a question numbered #6...

When I was reading the stimulus, a couple things stood out for me:
1) cable bridge does a better job in maintaining the beauty..than skyway
2) cost is not as important a concern as maintaining the beauty
3) maintaining the beauty is important, (assumption: so it needs to be preserved)

1) being the most obvious one that occurred to me, but I guess I was a little bit too excited when I saw (C), so I was biased and eliminated (E) without much consideration.

I guess again, I should have worked form wrong to right, but I wonder if you can shed more lights on why (C) is wrong. Is it because it is a restatement of the premise or something else?

Thanks in advance.
 Zach Foreman
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#67263
silent,
C is definitely the trap answer. An assumption is a missing premise. It is both a. necessary to the argument's validity but also b. not there. So, yes, you are correct. C is just a restatement of the premise contained in the last sentence "the importance of maintaining the beauty of our river crossing" is equivalent to "The beauty of the river crossing must be preserved."

P1. Beauty of the crossing must be preserved or it is important to maintain the beauty of the river crossing
P2 (A cable bridge is a more beautiful river crossing than a concrete one)
Conclusion: We should build a cable bridge as a replacement rather than a concrete one, even though it is more expensive.

You want to 1. prephrase correctly 2. accurately match your prephrase. Your three points were good but not equivalent. You need to explicitly find a prephrase. Your first point is a good prephrase because it is the missing premise. The second point is just an amplification of the first. Your other two are not the same because they are simple rephrases (not preprhases!) of information in the stimulus. 1 is nowhere in the stimulus but *should* be. 2 and 3 are in the stimulus. You should think "Ok, it's an assumption question. The right answer will be the one that contains information not in the argument but that needs to be in the argument." If you did that, you would have chosen E.
 KG!
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#77259
It was difficult for me to see that answer C was talking about the level of preservation and the stimulus was not. I almost picked E, but then thought to myself C was the better answer.


My reasoning for not picking E was that how would we know that building a cable bridge will be more aesthetically pleasing. If that's the case then this is why C was the correct answer in my head. (because here the idea of beauty is being preserved) Clearly, I was wrong in this thought process and I felt confident in my answer choice.

Can someone address my thought process and again why C is wrong. It's not entirely clicking because it was wasn't obvious.

Thank you in advance!
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 KelseyWoods
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#77487
Hi KG!

Let's start by breaking down this argument again:

Conclusion: We should replace the old bridge with a cable bridge instead of a concrete skyway.

Premise: The extra cost of the cable bridge is justified by the importance of maintaining the beauty of the river crossing.

In Assumption questions, you're often looking for a missing link between the premises and the conclusion. Here, the conclusion is that we should spend more to build the cable bridge rather than a concrete skyway based on the premise that maintaining the beauty of the crossing is more important than the additional cost. But the author hasn't explicitly stated that the cable bridge would better maintain the beauty of the river crossing than the concrete skyway. If the author thinks that we should build the cable bridge over the concrete skyway because beauty is more important than cost, then the author must be assuming that the cable bridge is more beautiful than the concrete skyway.

This leads us to answer choice (E). Careful with how you phrased your hesitation toward (E): "how would we know that building a cable bridge will be more aesthetically pleasing." We don't know that it will because the author didn't explicitly state that. That's why it's an assumption--an assumption is simply an unstated premise; it's something that must be true if the conclusion is going to follow from the premises. If we should build the cable bridge instead of the concrete skyway because beauty is more important than cost, then the cable bridge better be more beautiful than the concrete skyway (because the premises already tell us that it's more expensive). Also, use the Assumption Negation Technique. If we negate (E) to say that building a cable bridge would not be more aesthetically pleasing than building a concrete skyway, that would kill our argument that we should build the cable bridge even though it's more expensive.

Answer choice (C) says that the beauty of the river crossing must be preserved, which is definitely tempting. But remember that our conclusion is still about building the cable bridge instead of the concrete skyway but the author has not explicitly told us that the cable bridge is more beautiful than the concrete skyway. So (C) is not a very good linking Assumption. Moreover, if we negate answer choice (C) to say that preserving the beauty of the river crossing is not necessary, that doesn't actually attack the argument that the beauty of the cable bridge outweighs its cost. Even if preserving the beauty of the river crossing is not absolutely necessary, it might still be the case that the difference in beauty between the two bridge options outweighs the difference in cost between them.

Hope this helps!

Best,
Kelsey

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