LR Question 25 Explanation
QUESTION TEXT: Interior decorator: All coffeehouses and restaurants a…
QUESTION TYPE: Must Be True
FACTS:
- Coffee or Restaurant ➞ Public Place
Comfortable➞Well Designed(For public places)- Well Designed ➞ Comfortable (contrapositive)
- Comfortable ➞ Spacious Interior
ANALYSIS: You can combine the 3rd and 4th claims to get this statement about public places:
Well Designed ➞ Comfortable ➞ Spacious Interior
This chain applies to coffeehouses or restaurants, since they are public places. So any well designed coffee house is spacious.
I didn’t draw the most statement. It doesn’t connect with anything. I prefer to leave most statements alone until I’ve drawn the rest of the diagram, as you generally can’t use them to form logical chains.
This most statement turned out to be useless fluff.
___________
- We know comfortable places have large interiors. But this answer mixes up necessary and sufficient. A large public place doesn’t have to be comfortable.
- This answer just gets the ‘most’ statement backwards. You can’t reverse a ‘most’ statement.
- There are lots of public places: museums, libraries, malls, subway stations. We know most well designed public places have artwork, but maybe the art is in the public places I listed and not in coffee houses.
- CORRECT. Coffee houses are public places. We know that well designed public places are comfortable, and that comfortable places are spacious. So any well designed coffeehouse is spacious. See the diagrams above.
- This answer confuses sufficient and necessary.
We only know:
‘Well designed ➞ comfortable ➞ spacious’
The reverse doesn’t have to be true. I’ve been in large, ugly coffee houses.
More Resources for Must Be True Questions
- Conditional Reasoning Article: Learn about conditional statements on the LSAT.
- LR Diagrams Guide: Learn how to draw LR diagrams.
- Intro to Conditional Reasoning: This intro course lesson covers conditional reasoning basics.
- Intro Course lesson: This intro course lesson covers Must Be True questions.
- Mastery Seminar lesson: This LR Mastery seminar lesson covers must be true questions.
I cannot seem to understand why “C” is wrong. I do see why “D” is correct. However, I cannot see why C is wrong as well. All Coffee houses are public places. Most well-designed public places feature artwork. Therefore, if a coffee house is well designed, it must feature artwork. I cannot work that out. Please help. Thanks.
You’re missing one small point here.
Premise: “Most well-designed public places feature artwork.” –> This means that when we look at all public places, more than 50% of them feature artwork.
From that premise, can we now conclude that (C), “most coffee houses that are well-designed feature artwork”?
What if there were 10000 well-designed public places in the world, and 500 of them were coffee houses.
To satisfy the premise, let’s say that 6000 of those well-designed public places featured artwork. But potentially, none of those well-designed public places that featured artwork were coffee houses. There’s a distinction between “most overall” (the premise) and “most coffee houses” (C).
Hi Graeme,
Based on your contrapositive of “If a public place is uncomfortable it is not well designed” (#3 in FACTS), it looks like you equate “Not uncomfortable” with “Comfortable.” But can’t “Not comfortable” be “neutral– neither comfortable nor uncomfortable”? In this case, then D would not necessarily be true.
None of the other answers must be true, and D seems like the best answer. That being said, I was hoping you could clarify the above point.
Thanks!
You’re right, the logical opposite of uncomfortable includes being both “comfortable” or perfectly neutral — neither comfortable nor uncomfortable. However, on the LSAT we are asked to use everyday common sense. The idea of being in a perfectly neutral state without in at least some way being comfortable or uncomfortable isn’t grounded enough in everyday reality for us to include it as a possibility here when we negate “uncomfortable”.