LSAT 154 – Section 1 – Question 09

LSAT 154 - Section 1 - Question 09

September 2017

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Question
QuickView		 Type Tags Answer
Choices		 Curve Question
Difficulty		 Psg/Game/S
Difficulty		 Explanation
PT154 S1 Q09
+LR
+Exp
Flaw or descriptive weakening +Flaw
Conditional Reasoning +CondR
A
21%
158
B
73%
164
C
3%
156
D
1%
151
E
2%
157
139
151
162
 +Medium 147.621 +SubsectionMedium

Gecko lizards are found in any environment where there is an abundant population of gnats. Gnats can survive only in wet climates. Because there are no gecko lizards living here, there must not be an abundant population of gnats here. Consequently, the climate here must not be wet.

Summarize Argument
The author concludes that the climate in this area is not wet. This is based on the following:
Abundant population of gnats → geckos found
Gnats → wet climate
There are no geckos in this area.
There isn’t an abundant population of gnats in this area.

Identify and Describe Flaw
The author confuses sufficient and necessary conditions in this statement: “Gnats can survive only in wet climates.” This establishes that having gnats present is sufficient to know that the climate is wet. But the author mistakenly believes that this implies the absence of an abundance of gnats proves that the climate is not wet. This overlooks the possibility that a climate can be wet even if there are aren’t many gnats present.

A
presumes, without providing justification, that gecko lizards can survive only in environments with abundant gnat populations
The author does not assume gnats are necessary for geckos. Rather, the author correctly uses the premise that asserts the presence of geckos is necessary for abundance of gnats. We know there are no geckos in the area, so that proves there isn’t an abundance of gnats.
B
presumes, without providing justification, that all wet environments contain abundant populations of gnats
The author assumes that if the climate in an area is wet, there will be an abundance of gnats. This is why the author believes the lack of abundance of gnats implies that a climate is not wet. This is flawed, because no premise tells us all wet climate areas have lots of gnats.
C
does not consider whether small populations of gnats can survive in climates that are not wet
A premise establishes that gnats can survive only in wet climates. So if an area is not wet, gnats cannot survive there.
D
does not mention whether gecko lizards eat anything besides gnats
The author didn’t need to mentions whether geckos eat other things. In fact, it’s not even clear whether geckos eat gnats. What’s in a geckos diet doesn’t affect the logic of the argument.
E
fails to establish that some gecko lizards could not survive in a dry climate containing only a small population of gnats
We already have a premise asserting that there are no geckos living in the area. So the author doesn’t need to establish that it’s impossible for geckos to live in certain areas. We already know geckos don’t live in this area, and the argument is about this area.

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LSAT PrepTest 154 Explanations

Section 1 - Logical Reasoning

Section 2 - Logical Reasoning

Section 3 - Reading Comprehension

Section 4 - Logical Reasoning

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