LSAT 138 – Section 4 – Question 01

LSAT 138 - Section 4 - Question 01

December 2012

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Question
QuickView		 Type Tags Answer
Choices		 Curve Question
Difficulty		 Psg/Game/S
Difficulty		 Explanation
PT138 S4 Q01
+LR
+Exp
Flaw or descriptive weakening +Flaw
Causal Reasoning +CausR
Net Effect +NetEff
A
2%
159
B
2%
156
C
1%
160
D
93%
164
E
1%
159
120
125
140
 +Easiest 146.393 +SubsectionMedium

Jim’s teacher asked him to determine whether a sample of a substance contained iron. Jim knew that magnets attract iron, so he placed a magnet near the substance. Jim concluded that the substance did contain iron, because the substance became attached to the magnet.

Summarize Argument: Phenomenon-Hypothesis
Jim concludes that a substance contains iron because it’s attracted to a magnet, and iron is a material that’s attracted to magnets.

Identify and Describe Flaw
This is a cookie-cutter example of an argument mistaking a sufficient condition for a necessary condition. Jim treats “containing iron” as though it were a necessary condition for being magnetic, even though it’s only sufficient. In other words, he ignores the possibility that the substance contains a magnetic material other than iron.

A
iron sometimes fails to be attracted to magnets
This possibility is irrelevant because the iron was attracted to the magnet in this case.
B
iron is attracted to other objects besides magnets
The argument is only concerned with whether being attracted to a magnet is enough to prove that a substance contains iron. Whether iron is also attracted to other objects has no bearing on that issue.
C
the magnet needed to be oriented in a certain way
Even if this were a requirement, the magnet would have to have been oriented correctly since it attracted the substance in this case.
D
magnets attract substances other than iron
This possibility undermines the conclusion because it means that the substance could be attracted to the magnet because it contains some magnetic material other than iron.
E
some magnets attract iron more strongly than others
The argument is only concerned with whether the magnet attracts the substance or not; the degree to which it attracts it is irrelevant.

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LSAT PrepTest 138 Explanations

Section 1 - Reading Comprehension

Section 2 - Logical Reasoning

Section 3 - Logical Reasoning

Section 4 - Logical Reasoning

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