LSAT 159 | Section 1 | Logical Reasoning: Q10

LR Question 10 Explanation

QUESTION TEXT: A recent study found that most individuals believe that …

QUESTION TYPE: Complete the Argument

CONCLUSION: At least some people are wrong about how much they sleep. (Implied conclusion)

REASONING:

• Most people believe they sleep less than most other people.
• This isn’t possible.

ANALYSIS: Let’s say you have ten people. Most would be six people. There are only four people left, which is not most. So, if those six people each believe that they sleep less than most other people, then at least some of them are mistaken.

How many need to be mistaken? Only a couple. Four of them could be correct, and two mistaken. That would mean four people truly sleep less than all of the other people (six people). So, those four would outsleep most people.

There. That’s the math for why some people must be mistaken. The trap answer says “most” people must be mistaken, but that goes too far.

___________

1. “Not true even in principle” is what makes this answer wrong. Each person has a belief about their own sleep, only. Obviously it is possible for one person to outsleep most people.
    
   No one believes “most people outsleep most people”. That wouldn’t be possible in principle, but it isn’t anyone’s belief.
2. You can be aware of how much you sleep, but be incorrect about whether this is comparatively more or less than other people sleep.
3. This goes too far in the other direction. The author has shown that some people are mistaken. See the math in the analysis section for a walkthrough.
    
   If you’re still not convinced, consider this. This answer says most people are mistaken, E says that some people are mistaken. If most people are mistaken about sleep, then some people have to be. So if this answer is right, then E is also right, and you can’t have two right answers. Both C and E are talking about the same belief: do you mistakenly believe you sleep less than others?
4. We don’t know anything about how long people believe they should sleep. The LSAT makes a strict separation between what is true vs. what you should do.
5. CORRECT. A majority of people can’t sleep less than a majority of others. You can’t have two majorities.
    
   So at least some of the people who believe they sleep less than most other people are wrong.