Summarize Argument
The pundit concludes that the two major political parties in the city have become sharply divided on issues. He supports this by noting that in the last four elections, the parties were separated by less than 1% of the vote.
Identify and Describe Flaw
The pundit concludes that the parties are sharply divided simply because they were separated by less than 1% of the vote in recent elections. He assumes that a close vote indicates a sharp division but doesn’t provide evidence for this. It's possible that the close vote actually shows that the two parties have very similar views and are united.
A
confuses the cause of the sharp division with an effect of the sharp division
The pundit actually doesn’t address any causes or effects of the sharp division, so he can’t be confusing the two. Instead, he simply argues that the close vote is evidence of a sharp division.
B
presumes, without argument, that sharp division is a bad thing
The pundit assumes that a close vote is evidence of sharp division, but he never claims or assumes that sharp division is a bad thing.
C
has a conclusion that is merely a restatement of one of its premises
This is the cookie-cutter flaw of circular reasoning. The pundit doesn’t make this mistake. His premise doesn’t support his conclusion very well, but the two are distinct from one another.
D
fails to indicate how what is happening in one city compares with what is happening in other cities
The pundit is only addressing the two major political parties “in this city.” How the elections in this city compare to the elections in other cities is irrelevant.
E
takes for granted that an almost even division in votes indicates a sharp division on issues
The pundit assumes that a close vote indicates a sharp division on issues, but he gives no evidence to support this assumption. It’s possible that an almost even division in votes actually indicates that the two parties are united.
Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that the reason Bach is remembered is that he was such a prolific composer. This is based on the fact that Bach wrote more than a thousand full compositions, which the author believes would inevitably have resulted in some outstanding compositions that would survive for a long time.
Notable Assumptions
The author assumes that there is no other explanation for why Bach is remembered.
A
Several of Bach’s contemporaries who produced more works than he did have been largely forgotten.
This provides evidence that being a prolific composer is not enough to make one remembered. This calls into question the author’s explanation for why Bach is remembered.
B
There are a few highly regarded composers who wrote a comparatively small number of compositions.
The author never suggested that writing a smaller number of compositions would make it impossible to be highly regarded or remembered. The author’s theory is just that writing a lot of compositions can make one remembered.
C
Bach wrote many compositions that were considered mediocre in his lifetime, and a large proportion of these compositions have been forgotten.
The author acknowledges that Bach could have written many mediocre compositions. But, the author believes that at least some were outstanding, they could allow Bach to be remembered.
D
The exact number of Bach’s compositions is not known, since many of them have been lost to posterity.
We don’t need to know the exact number of compositions. We still know that he wrote more than a thousand full compositions, which is a large number.
E
Some great creative geniuses are remembered because they had a very high ratio of outstanding works to mediocre works.
The author never suggested that having a high ratio of outstanding works to mediocre works could never be a reason someone is remembered. The author is simply arguing that in Bach’s case, that explanation doesn’t apply.
Summarize Argument
The taxi driver concludes he made the right decision to shut off his air conditioning while climbing a steep hill. Why? Because doing so prevented his fuel efficiency from decreasing significantly.
Notable Assumptions
The taxi driver assumes it was better to prevent bad fuel economy than to keep the air conditioning turned on. This means assuming the passengers’ discomfort and complaints are outweighed by the benefits of better fuel efficiency.
A
A taxi driver should not run a cab’s air conditioner if doing so would make it difficult to maintain a consistent speed.
This principle doesn’t apply. The taxi driver doesn’t say it would be difficult to run the air conditioner and maintain a consistent speed—in fact, he says it’s possible.
B
A taxi driver should run a cab’s air conditioner only if doing so does not cause fuel economy to drop below normal levels.
This principle justifies the taxi driver’s decision. It means a taxi driver shouldn’t run the air conditioning if it causes below-normal fuel economy, regardless of any complaints.
C
A taxi driver should try to balance concern for fuel economy with concern for passenger comfort.
Without instruction on how to weigh those concerns, this principle is insufficient to justify the taxi driver’s decision. It doesn’t say concerns about fuel economy should outweigh concerns about passenger comfort.
D
A taxi driver should always act in a way that is most likely to ensure customer satisfaction.
If anything, this weakens the argument. It suggests the taxi driver should weigh passenger comfort, which clearly affects customer satisfaction, more heavily than fuel economy, which doesn’t.
E
A taxi driver’s turning off air-conditioning for a short period of time is acceptable only if passengers do not complain.
This weakens the taxi driver’s argument. Since the passengers complained, it implies his turning off the air conditioner was unacceptable.
"Surprising" Phenomenon
Why do loons often attempt to take over an occupied lake when they could just settle in an unoccupied lake instead?
Objective
The right answer will describe either a benefit of settling in an occupied lake, despite the effort the returning loons must expend to oust another loon couple, or a drawback of settling in an unoccupied lake.
A
Most of the nearby vacant lakes have served as successful loon breeding territory in the past.
This is the opposite of what we need. If most of the nearby vacant lakes are already proven to be suitable breading territories, it would make sense for the loons to settle in those lakes rather than fighting over the occupied ones!
B
Contests for occupied breeding territory may be initiated either by male loons or by female loons.
This doesn’t matter. We want to know why these contests are taking place at all, not who starts them—why wouldn’t the loons just settle in a territory they wouldn’t have to compete over?
C
Loons that intrude on an occupied breeding territory are successful in ousting its residents about half the time.
This doesn’t help. It doesn’t matter how often the loons are successful in their attempted takeovers. We just want to know why they’re trying to take the occupied lakes in the first place.
D
Loons frequently determine that a lake is a suitable breeding territory by observing the presence of a breeding pair there.
This is the explanation we need! When loons see another breeding pair in a lake, they take that pair’s presence as evidence that the lake is a good place for breeding. Instead of taking their chances with an untested lake, they try to get the lake someone’s already vetted!
E
Lakes that are perfectly suitable for loon breeding have fish for food, a site for a nest, and a sheltered area to rear chicks.
This answer choice would be helpful if it told us that the unoccupied lakes lack some of these factors that make lakes suitable for breeding, but as it stands, “E” doesn’t give us any information that would help explain why loons don’t always settle in unoccupied lakes.
Summary
Engineers are challenged with designing a self-driving robotic car that avoids common traffic problems like crashes and congestion. Similarly, these problems affect fish traveling together in schools. Methods fish use to navigate ensure these problems are less common compared with that among cars on the road.
Strongly Supported Conclusions
Hence, the methods fish use to navigate could help engineers design a self-driving robotic car that avoids common traffic problems.
A
constructing a self-driving robotic car requires expertise in fish biology
This answer is unsupported. The stimulus does not involve conditional reasoning. We don’t know if expertise in fish biology is a necessary condition for constructing self-driving robotic cars.
B
the best drivers use the same navigational principles that fish use in schools
This answer is unsupported. We don’t know from the stimulus what methods the best drivers use. The stimulus addresses common traffic problems generally.
C
it is always advisable for engineers facing design challenges to look to the natural world for guidance in addressing those challenges
This answer is unsupported. To say that this is always advisable is too strong. We know from the stimulus that this may be one instance, but we don’t know if there are other circumstances where the natural world would guide engineers addressing challenges.
D
studying the principles fish use to navigate in schools could help engineers to design a self-driving robotic car that avoids common traffic problems
This answer is strongly supported. The stimulus employs reasoning by analogy. If schools of fish avoid problems by navigating using certain methods, it is possible these methods could possibly be useful to engineers when designing self-driving robotic cars.
E
a self-driving robotic car using the navigational principles that fish use in schools would be better than a human-driven car at avoiding crashes and congestion
This answer is unsupported. We don’t know from the stimulus what frequency human-driven cars are involved in traffic problems compared with self-driving robotic cars.