Section Types Logical Reasoning

All highly successful salespersons are both well organized and self-motivated, characteristics absent from many salespersons who are not highly successful. Further, although only those who are highly successful are well known among their peers, no salespersons who are self-motivated regret their career choices.

Summary

The stimulus can be diagrammed as follows:

Notable Valid Inferences

Well known people don’t regret their career choices.

If someone is not well organized, then they are not well known.

If someone is not self motivated, then they are not well known.

A

No self-motivated salespersons who are not highly successful are well organized.

This could be false. We don’t know anything about the subset of salespersons who are both self motivated and not highly successful. We can’t say whether or not they are well organized.

B

All salespersons who are well organized but not highly successful are self-motivated.

This could be false. We don’t know anything about the group of salespersons who are both well organized and not highly successful.

C

No salespersons who are well known among their peers regret their career choices.

This must be true. This answer can be rewritten as “Well Known→ /Regret.” As shown in the diagram, by chaining the conditional claims, we see that not regretting career choices is a necessary condition of being well known.

D

All salespersons who are not well organized regret their career choices.

This could be false. “/WO→R” is not a valid inference that shows up on the diagram. It could be the case that some salesperson is not well organized and also does not regret their career choice.

E

All salespersons who do not regret their career choices are highly successful.

This could be false. (E) is an incorrect reversal of the conditional relationship. We know that all people who are highly successful do not regret their career choices. (HS→/R). (E) says “/R→HS.” This incorrectly flips the sufficient and necessary conditions.

23 comments

LSAT 119 - Section 4 - Question 24

February 21, 2014

Biologist: We know the following things about plant X. Specimens with fuzzy seeds always have long stems but never have white flowers. Specimens with curled leaves always have white flowers, and specimens with thorny seedpods always have curled leaves. A specimen of plant X in my garden has a long stem and curled leaves.

Summary

Specimens with fuzzy seeds have long stems.

Specimens with fuzzy seeds lack white flowers.

Specimens with curled leaves have white flowers.

Specimens with thorny seedpods have curled leaves.

The biologist’s plant has a long stem and curled leaves.

Very Strongly Supported Conclusions

The biologist’s specimen has white flowers.

The biologist’s specimen lacks fuzzy seeds.

A

It has white flowers and thorny seedpods.

Unsupported. We know the specimen has white flowers, but we don’t know if it has thorny seedpods. Careful with negations—“no curled leaves” is a sufficient condition for “no thorny seedpods”, but that doesn’t mean “curled leaves” is a sufficient condition for “thorny seedpods”!

B

It has white flowers but lacks thorny seedpods.

Unsupported. We know the specimen has white flowers, but we don’t know if it has thorny seedpods. Careful with negations—“no curled leaves” is a sufficient condition for “no thorny seedpods”, but “curled leaves” tells us nothing about whether a specimen has thorny seedpods!

C

It has white flowers but lacks fuzzy seeds.

Very strongly supported. As shown below, by chaining the conditional claims, we see that “no curled leaves” is a necessary condition of both “fuzzy seeds” and “no white flowers”. Having curled leaves, then, is a sufficient condition for “white flowers” and “no fuzzy seeds”!

D

It has fuzzy seeds and thorny seedpods.

Anti-supported. Because the specimen has curled leaves, we know that it doesn’t have fuzzy seeds. We can’t determine whether it has thorny seedpods—“no curled leaves” is a sufficient condition for “no thorny seedpods”, but “curled leaves” tells us nothing about thorny seedpods!

E

It lacks both white flowers and fuzzy seeds.

Anti-supported. Because the specimen has curled leaves, we know that it has white flowers. It is true that it doesn’t have fuzzy seeds.

17 comments

LSAT 119 - Section 4 - Question 25

February 21, 2014

Unquestionably, inventors of useful devices deserve credit for their ingenuity, but the engineers who help develop an invention get too little recognition. Although inventors sometimes serve as their own engineers, more often, engineers must translate an inventor’s insight into something workable and useful. Therefore, engineers also deserve credit for their contribution.

Summarize Argument

In addition to inventors, engineers deserve credit for their contribution to inventions. They don’t usually get enough recognition, even though engineers are tasked with turning an inventor’s insight into something tangible and useful.

Identify Argument Part

This part of the argument is a small concession. The argument does not apply in every case because sometimes inventors act as their own engineers, so they do get the credit they deserve. It qualifies the scope of the claim, showing that it applies in most, but not all, cases.

A

It separates the practical and theoretical aspects of the argument.

This statement does not separate the practical and theoretical, it just explains some cases where the argument does not apply. The argument does not really have practical/theoretical aspects to separate.

B

It indicates that the problem identified in the argument does not arise in every instance.

This accurately describes how this statement functions. It explains the situations in which the problem of recognition does not apply: when inventors serve as their own engineers.

C

It supports an earlier statement regarding what is at issue in the argument.

It doesn’t support what is at issue - or support anything. Instead, it shows exceptions to the issue.

D

It concedes that a distinction on which the argument relies is unclear.

While there is a concession occurring, it is not saying that the distinction between inventor and engineer is unclear. The distinction is clear, there are just cases where one individual acts as both.

E

It introduces an alternative solution to the problem the argument is addressing.

The author is not suggesting that inventors be their own engineers, they are suggesting that they should get the credit that is due to them.

6 comments