Summarize Argument
The author concludes that individuals who buy new cars today spend, on average, a larger amount relative to their incomes on a car than individuals spent 25 years ago. This is based on the fact that over the last 25 years, the average price paid for a new car has steadily increased in relation to the average individual income.
Notable Assumptions
The author assumes that the proportion of individuals who are buying cars today hasn’t significantly gone down. After all, if the proportion of individuals who buy cars has gone down, then it’s possible individuals still spend the same proportion of their income on cars; but other buyers (such as families or businesses) are paying a higher price and raising the average price of a car.
A
There has been a significant increase over the last 25 years in the proportion of individuals in households with more than one wage earner.
So, a higher proportion of households have more than one wage earner. But we’re talking about “individuals who buy new cars.” (A) doesn’t suggest that more households are buying a new car together.
B
The number of used cars sold annually is the same as it was 25 years ago.
The stimulus concerns changes in average price of a new car in relation to average income. The number of cars sold doesn’t affect average price of a car.
C
Allowing for inflation, average individual income has significantly declined over the last 25 years.
If income has gone down, that tends to support the position that individuals who buy new cars are spending a higher portion of their income than such individuals did 25 years ago.
D
During the last 25 years, annual new-car sales and the population have both increased, but new-car sales have increased by a greater percentage.
The stimulus concerns changes in average price of a new car in relation to average income. How many new cars are bought in relation to the population doesn’t affect the average price of a new car or how it relates to the average income.
E
Sales to individuals make up a smaller proportion of all new-car sales than they did 25 years ago.
This shows how the increase in average new car price can be explained by a greater portion of sales to non-individuals (such as a business). So, the increase in average price in relation to individual income doesn’t have to mean individuals are paying more for their cars.
Don't worry if you didn't get this exceptionally difficult question correct. Later lessons in Advanced Logic will help to elucidate the concepts behind this question.
To see why (E) is incorrect, first recall what the practice in the stimulus was in a general form. Stated broadly, it was the practice of having people set standards from which they themselves would later benefit. This is why having executives sit on boards to determine salaries of other executives is not a great idea. This is also why having doctors sit on juries to determine damages for malpractice suits for other doctors is not a great idea. Whatever standard they set would later be used for them.
Now how does (E) do any of that? Sure you have a group of people. And there's something something money. That's it. Each person in the group is directly evaluating each other, confidentially but who cares. There's a set amount of money, say $100, to be given to the group consisting of say 5 people. Who gets how much? Well, that depends on how each person is evaluated by their peers. So... I guess if I'm in the group, I'm incentivized to give everyone else a low rating so that I could get more of the $100 pie? I guess. Wait but what am I even doing. I'm supposed to be setting a financial standard that would later benefit me. That's not what I'm doing at all. I'm just directly screwing my co-workers over so that I benefit.
Summary
The author concludes that some students with part-time jobs do not walk to school. His reasoning is that every student who walks to school goes home for lunch. Or, in contrapositive form, that all students who don’t go home for lunch don’t walk to school.
Missing Connection
The conclusion is about students with part-time jobs, but they aren’t mentioned in the premise. We need to bridge this gap to reach the conclusion that some students with part-time jobs do not walk to school.
By taking the contrapositive of the premise, we inferred that all students who don’t go home for lunch don’t walk to school. So, if at least some students with part-time jobs don’t go home for lunch, then some of them wouldn’t walk to school. This would guarantee the argument’s conclusion.
By taking the contrapositive of the premise, we inferred that all students who don’t go home for lunch don’t walk to school. So, if at least some students with part-time jobs don’t go home for lunch, then some of them wouldn’t walk to school. This would guarantee the argument’s conclusion.
A
Some students who do not have part-time jobs go home for lunch.
This can’t be correct, because it tells us about some students who don’t have part-time jobs. Our conclusion is about students who do have part-time jobs. A “some” statement’s contrapositive isn’t automatically valid. So this tells us nothing about students with part-time jobs.
B
Every student who goes home for lunch has a part-time job.
This doesn’t help us reach our conclusion, because all it lets us infer is that some students with part-time jobs go home for lunch. We want to conclude that some students with part-time jobs do not walk to school.
C
Some students who do not have part-time jobs do not go home for lunch.
This can’t be correct, because it tells us about some students who don’t have part-time jobs. Our conclusion is about students who do have part-time jobs. A “some” statement’s contrapositive isn’t automatically valid. So this tells us nothing about students with part-time jobs.
D
Some students who do not go home for lunch have part-time jobs.
Every student who doesn’t go home for lunch doesn’t walk to school. So, if some students with part-time jobs don’t go home for lunch, some students with part-time jobs don’t walk to school. Note that “some” is bidirectional: saying some As are Bs is equivalent to saying that some Bs are As.
E
Every student who goes home for lunch walks to school.
This doesn’t mention students with part-time jobs, so it can’t be correct. We need an answer that bridges the gap between the premise and the conclusion.
A
When webs of many different species of spider were illuminated with a uniform source of white light containing an ultraviolet component, many of these webs did not reflect the ultraviolet light.
Irrelevant. The author never said that Glomosus spiderwebs are the only spiderwebs that reflect ultraviolet light.
B
When the silks of spiders that spin silk only for lining burrows and covering eggs were illuminated with white light containing an ultraviolet component, the silks of these spiders reflected ultraviolet light.
Like (A), this is irrelevant. We don’t care about other spiderwebs that reflect ultraviolet light.
C
When webs of the comparatively recently evolved common garden spider were illuminated with white light containing an ultraviolet component, only certain portions of these webs reflected ultraviolet light.
Irrelevant. We don’t care about other spiderwebs that reflect ultraviolet light.
D
When Drosophila fruit flies were placed before a Glomosus web and a synthetic web of similar pattern that also reflected ultraviolet light and both webs were illuminated with white light containing an ultraviolet component, many of the fruit flies flew to the Glomosus web.
The author argues that the specific patterns of ultraviolet light attract insects. This suggests something else about the Glomosus spiderwebs is actually what attracts them.
E
When Drosophila fruit flies were placed before two Glomosus webs, one illuminated with white light containing an ultraviolet component and one illuminated with white light without an ultraviolet component, the majority flew to the ultraviolet reflecting web.
Between the otherwise identical Glomosus spiderwebs, insects chose the one with ultraviolet reflections. This strengthens the idea that ultraviolet reflections, and not something else about the spiderwebs, are what attract insects.
Summary
Poets preserve languages, because only poetry cannot be translated well. If we could get everything written in a translation, then we would not bother to learn a language. Therefore, since we cannot observe the beauty of poetry except in the language in which it is written, we have motivation to learn the language.
Strongly Supported Conclusions
We should note that, since this is an “except” question, any strongly supported conclusion would be an incorrect answer choice. We’re looking for an answer choice that is unsupported or least supported. Some strongly supported conclusions could include:
If we bother to learn a language, then there must be poetry in that language.
Preserving a language involves motivating at least some people to learn that language.
The desire to witness the beauty of poetry motivates at least some people to learn a language.
If we bother to learn a language, then there must be poetry in that language.
Preserving a language involves motivating at least some people to learn that language.
The desire to witness the beauty of poetry motivates at least some people to learn a language.
A
All nonpoetic literature can be translated well.
The stimulus concedes that any nonpoetic form of literature can be translated well. We are told only poetry cannot be translated well.
B
One purpose of writing poetry is to preserve the language in which it is written.
The stimulus does not provide any information regarding the purpose of writing poetry. We only know, rather, the consequences or results of writing poetry.
C
Some translations do not capture all that was expressed in the original language.
The stimulus concedes that some translations do not capture everything expressed in the original language. Our main example is poetry, and we know from the stimulus that only poetry cannot be translated well.
D
The beauty of poetry is not immediately accessible to people who do not understand the language in which the poetry was written.
The stimulus concedes that one cannot understand the beauty of poetry except in the language it is written in. If someone does not understand that language, the poetry’s beauty would not be immediately accessible.
E
Perfect translation from one language to another is sometimes impossible.
The stimulus concedes that sometimes perfect translation between languages is impossible. Our main example is poetry, and we know from the stimulus that only poetry cannot be translated well.