LSAT 155 | Section 2 | Logical Reasoning: Q9

LR Question 9 Explanation

QUESTION TEXT: Rodents are small, gnawing mammals characterized by…

QUESTION TYPE: Most Strongly Supported

FACTS:

1. Rodents are small gnawing mammals characterized by their chisel-like incisor teeth.
2. Most North American mammal species are not rodent species.
3. Most individual mammals in North America are rodents.

ANALYSIS: One important thing to note about this stimulus is what might seem like a paradox. Fact 2 says that most mammal species are not rodents, but Fact 3 says that most individual mammals are rodents. If you’re good at Paradox questions, you’ve probably already figured out what this means. Most mammal species in North America aren’t rodent species, but there are so many individual rodents that they outnumber the other mammals overall.

We can also infer, from Facts 1 and 3, that most individual mammals have chisel-like incisor teeth and are small gnawing mammals, because this is true of rodents.

___________

1. This looks like our inference above, but this is talking about species, not individuals. Most mammals are rodents, but most mammal species are not. So this doesn’t follow.
2. CORRECT. Most mammal species aren’t rodents, but most mammals are. This means that there must be a lot of individual rodents, enough to outweigh the others.
3. We can’t get to this from our information. We don’t know anything about other places, so we can’t say North America has more than elsewhere.
4. This is starting along the right lines, but misses the point. It doesn’t matter whether the species with the most individual members is a rodent. If rodent species generally have a lot of individuals, they will still outnumber the rest.
5. This is the same problem as C. We don’t know anything about anywhere other than North America, so we can’t make a comparative inference.

Recap: The question begins with “Rodents are small, gnawing mammals characterized by”. It is a Most Strongly Supported question. Learn how to master LSAT MSS questions on the LSAT Logical Reasoning question types page.