LSAT 150 – Section 3 – Question 09

LSAT 150 - Section 3 - Question 09

June 2018

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Question
QuickView		 Type Tags Answer
Choices		 Curve Question
Difficulty		 Psg/Game/S
Difficulty		 Explanation
PT150 S3 Q09
+LR
Flaw or descriptive weakening +Flaw
Math +Math
Part v. Whole +PvW
A
4%
156
B
2%
154
C
85%
163
D
4%
154
E
6%
156
138
146
155
 +Medium 148.057 +SubsectionMedium

Marketing agent: A survey of my business clients reveals that, of those who made a profit last year, 90 percent made at least $100,000 in profit for the year. In prior years, not one of these businesses made an annual profit of more than $10,000. So, 90 percent of my business clients increased their profits at least tenfold last year.

Summarize Argument
The marketing agent concludes that 90% of his clients increased their profits at least tenfold last year. He supports this by saying that 90% of his clients who made a profit last year earned at least $100,000, and none of them had earned more than $10,000 in previous years.

Identify and Describe Flaw
The marketing agent concludes that 90% of his clients increased their profit tenfold last year based only on the fact that 90% of his profitable clients did so.

This is the part-to-whole flaw. The agent assumes that what’s true of a subset of his clients applies to all of his clients. But it’s possible that only a few clients were profitable last year, and while 90% of them increased their profits tenfold, most clients didn’t profit at all.

A
overlooks the possibility that the business clients who made more than $100,000 last year made only slightly more than $100,000
This doesn’t impact the agent’s conclusion. Even if these clients made only slightly more than $100,000, they still increased their profits tenfold. Either way, he assumes that what’s true of his profitable clients is also true of all his clients.
B
fails to explain why some of the business clients who made a profit did not increase their profits at least tenfold last year
The agent doesn’t explain why 10% of his profitable clients didn’t increase their profits tenfold, but he doesn’t need to. He only addresses those clients who did increase their profits tenfold, assuming that they’re representative of all his clients.
C
draws a conclusion about all of the business clients from premises about the business clients who made a profit last year
The agent concludes that all his clients increased their profits tenfold last year based on premises about his profitable clients. But what if he only had a few profitable clients? In that case, it’s not true that 90% of his clients increased their profits tenfold.
D
treats conditions that are sufficient for making a profit as though they are necessary for making a profit
This is the cookie-cutter flaw of confusing necessary and sufficient conditions. The marketing agent doesn’t make this mistake; his argument doesn’t rely on conditional logic. Instead, he assumes that what is true of one subset of his clients is also true of all his clients.
E
overlooks the possibility that not all of the business clients made an annual profit of more than $10,000 last year
The marketing agent actually allows for this possibility. 90% of his profitable clients made $100,000, but the other 10% might have made less than $10,000. Also, the clients that were not profitable certainly made less than $10,000 because they didn't make any profit at all.

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LSAT PrepTest 150 Explanations

Section 1 - Reading Comprehension

Section 2 - Logical Reasoning

Section 3 - Logical Reasoning

Section 4 - Reading Comprehension

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