LSAT Discussion Forum

I think your analysis is fine, especially with the limited time. You diagrammed the two statements that you did diagram correctly, and you got to the right answer, so that is a good approach to take.

Best,
Dan

Thanks Dan.

Hi PowerScore Staff,

I successfully got this right, but I am not sure why C is wrong as I go back through it.

I made the inferences to get to D, and eliminated A, B, and E. But isn't it still true that a well-designed coffeehouse will feature artwork?

The post above says, "Answer choice (C): Since the stimulus has not established that coffeehouses are well-designed public spaces, this application of the formal logical from the second sentence is not supported"
While I agree that the stimulus doesn't directly link coffeeshops to well designed, if it is supposed by an answer choice, isn't it possible that they are well designed? And if so, it must feature artwork. What am I missing?

Hi Deck,

In this Must Be True question, answer choice (C) is unsupported because the stimulus doesn't allow us to draw any conclusions about the proportion of well designed coffee houses that feature artwork, since "well designed coffee houses" is a numerically undefined subset of "well defined public places."

The stimulus tells us that all coffee houses and restaurants are public places, and that most well designed public places feature artwork.

Let's assume, for the purpose of this example, that there are 100 public places in the universe, 10 of which are coffee houses. Even if all 100 of those public places are well-designed, it's still possible for 51 (i.e. most) of those public places to feature artwork, while all 10 of the coffee houses fall in the remaining 49 that have bare, boring, artless walls.

I hope that helps, and happy studying!

- Ben DiFabbio
PowerScore LSAT Instructor

Hi I am also confused as to why this is wrong. First off my first question is what is the correct approach to take when coming to a question that has formal logic. Do you diagram everything then do the contrapositives?
And what is the deal with "any' and"most''

please help I am so so confused

Erica,

I'm not sure which choice you are confused about since you didn't identify one. I assume you mean (C).

The best approach is to distinguish between rules that can be linked and those that can't. One technique you can use is to diagram. "All" and "Any" are sufficiency indicators.

1st sentence: Coffeehouse or Restaurant Public Place (I am dropping the Public Place from the rest)
2d sentence: Well Designed Artwork
3d clause: -Comfortable -Well designed (this also means Well Designed Comfortable)
4th clause: Comfortable Spacious (this also means -Spacious -Comfortable)

From this, we know:

Well Designed Comfortable Spacious, and
-Spacious -Comfortable -Well Designed.

It's difficult to do anything with the "most," because you'll notice that we'd have to double back (a Mistaken Reversal) to try to use it. Now, (C) might make a bit of sense if Coffeehouses were the only public spaces. But the "Most" rule is about all public places--and at a minimum, that includes Restaurants (and could include other unmentioned places). You might not need very many Coffeehouses to satisfy the "most" if many of the Restaurants had art.

(D), on the other hand, just applies the inference we're able to make that if something is well designed it is spacious.

Hi, I'm having some trouble understanding why C is wrong and D is right. For C, the explanation says that "the stimulus has not established that coffeehouses are well-designed public spaces," but I feel like that doesn't matter - the answer choice gives us a scenario where most coffeehouses are well designed, and since a coffeehouse is a public place, it follows that a well designed coffee house is a well designed public place, and should therefore feature artwork.

And for D, again the stimulus does not establish that coffeehouses are well-designed public spaces, but we are told that in this scenario in the answer choice, the coffeehouses/restaurants are well designed and so should have the properties of well-designed public spaces. My issue with D is the logical opposite of uncomfortable - for D to be right, we'd have to say the logical opposite of uncomfortable is comfortable. But that doesn't seem right. The logical opposite would be NOT uncomfortable, which doesn't necessarily mean comfortable.

Can someone please clear up my misunderstanding? And as far as the reason that C is wrong in the explanation ("Since the stimulus has not established that coffeehouses are well-designed public spaces, this application of the formal logical from the second sentence is not supported"), that doesn't make much sense to me and would also make D an incorrect choice. Thanks!

Hi bukkaabh,

The real problem with answer choice C is we don't know how many well-designed coffeehouses there are relative to all the well-designed public places. What if there are only 5 well-designed coffeehouses, and there are 5,000 well-designed public places? Would we be required to say that most of those coffeehouses feature artwork? Not at all. In that circumstance, it might be that none of those 5 coffeehouses feature artwork, and there would still be plenty of other well-designed public places to satisfy the stimulus statement that most (2,501) of them feature artwork.

The term uncomfortable is properly interpreted as the logical opposite of comfortable. The term could be expressed identically as "not comfortable." A rough rule of thumb there would be that any term that expresses the absence of a positive is its positive's logical opposite. So there is no problem with reading the contrapositive of "If it is uncomfortable, it is not well-designed," as "If it is well-designed, then it is comfortable."

I hope this helps!

Jeremy

I did not make the assumption that a public place can either be comfortable or uncomfortable with no middle ground, which was the key to answer this question.

I'm also not sure how I was supposed to arrive at the assumption while reading the stimuli.

But I'll keep an eye on future LR drill questions and see if it comes up frequently, so I can just convert everything to logical notations and dichotomous contrapositives.

Hi bruceg!

I can understand the confusion. I think it is probably safe to say that if you see two words that are the same but one has the prefix "un-," then this denotes the negation of that word.

Here, we have some conditional statements:

Uncomfortable Well designed

Comfortable Spacious interior

You rightly note that we need to change one of these a bit for it connect to the other conditional reasoning. We can take the contrapositive of the first statement, which would be:

Well designed Uncomfortable

Since the prefix "un-" already is negating "comfortable," this is a double negation, so can be rewritten as:

Well designed Comfortable

This lets us connect the two diagrams into a chain:

Well designed Comfortable Spacious interior

This can be reduced to:

Well designed Spacious interior

This last diagram is what is reflected in answer choice (D).