Summary
At the end of each year in Country Q, there’s a count of the country’s total available coal supplies.
The total available coal supplies is the total amount of coal that has been mined throughout the country, but not yet used.
At the end of 1991 the total available coal supplies was lower than it was at the end of 1990.
Country Q has not imported or exported any coal since 1970. (So Country Q did not send any coal to another country and did not get coal from another country in 1991.)
The total available coal supplies is the total amount of coal that has been mined throughout the country, but not yet used.
At the end of 1991 the total available coal supplies was lower than it was at the end of 1990.
Country Q has not imported or exported any coal since 1970. (So Country Q did not send any coal to another country and did not get coal from another country in 1991.)
Notable Valid Inferences
Country Q consumed more coal in 1991 than it mined in 1991. This must be true because the total available coal supplies decreased from the end of 1990 to the end of 1991. If the country had mined more coal in 1991 than it had consumed that year or an equal amount, then the total available coal supplies would have increased or stayed the same.
A
In Country Q, more coal was mined in 1990 than was mined in 1991.
Could be false. We don’t know how much was mined in 1990 compared to 1991. In order to know something about the amount mined in 1990, we’d need to know how the coal supplies changed from the end of 1989 to the end of 1990.
B
In Country Q, the amount of coal consumed in 1991 was greater than the amount of coal mined in 1991.
Must be true. If (B) were not true, then the coal supplies would have increased or stayed the same from 1990 to 1991. But it decreased. So more was consumed than mined in 1991.
C
In Country Q, the amount of coal consumed in 1990 was greater than the amount of coal consumed in 1991.
Could be false. We don’t know how much was consumed in 1990 compared to 1991. In order to know something about the amount consumed in 1990, we’d need to know how the coal supplies changed from the end of 1989 to the end of 1990.
D
In Country Q, the amount of coal consumed in 1991 was greater than the amount of coal consumed in 1990.
Could be false. We don’t know how much was consumed in 1990 compared to 1991. In order to know something about the amount consumed in 1990, we’d need to know how the coal supplies changed from the end of 1989 to the end of 1990.
E
In Country Q, more coal was consumed during the first half of 1991 than was consumed during the first half of 1990.
Could be false. We don’t know how much was consumed in 1990 compared to 1991. We also don’t know when, within each year, any coal consumption took place. Maybe coal consumption was equal in the first half of each year.
Summarize Argument: Phenomenon-Hypothesis
The author concludes that there’s no need to look further for an explanation of the difference between the results the university study arrived at and the results the governmental study arrived at because each study used a different method of investigation.
Identify and Describe Flaw
The author reasons that since the university study and governmental study used different methods of investigation, there’s no need to look for another explanation of the studies arriving at different results. However, the argument is flawed because the author fails to consider that two studies using different methods of investigation doesn’t guarantee that they’ll arrive at different results. Different investigation methods can arrive at the same result.
A
distinguish between a study produced for the purposes of the operation of government and a study produced as part of university research
We don’t know that the governmental study was produced for the purpose of the operation of government. The government could’ve produced it for a different reason.
B
distinguish between a method of investigation and the purpose of an investigation
The author only discusses the method of investigation for each study. The author doesn’t discuss purpose.
C
recognize that only one of the studies has been properly conducted
We have no idea if either of the studies have or haven’t been properly conducted.
D
recognize that two different methods of investigation can yield identical results
The argument commits this flaw. The author argues that the studies arriving at different results is explained by them using different methods of investigation, without recognizing that the studies could’ve arrived at the same results with different methods of investigation.
E
recognize that varying economic conditions result in the average workweek changing in length
The argument isn’t concerned with economic conditions. The author only argues that the studies arriving at different results is explained by them using different methods of investigation.
Summary
The author concludes that differences in camera lens resolution are irrelevant for practical photography. Why? Because all modern lenses project far more detail onto film than any photographic film can reproduce in a developed image.
Notable Assumptions
What if differences in resolution could be important to some aspect of practical photography besides the amount of detail projected onto film? The author assumes that there’s no other way in which differences in resolution could be relevant to practical photography.
This isn’t a question where I’d go in with a specific prediction about what the author assumes. Let’s keep an open mind.
This isn’t a question where I’d go in with a specific prediction about what the author assumes. Let’s keep an open mind.
A
The definition of the term “resolution” does not capture an important determinant of the quality of photographic instruments and materials.
The author could very well agree that “resolution” captures something important about the quality of photographic instruments and materials, such as camera lens and film. The point, however, is that the differences in resolution of camera lens aren’t practically relevant. “Resolution” is still an important feature, but the differences in camera lens resolution don’t have to be.
B
In determining the amount of detail reproduced in the developed photographic image, differences in the resolutions of available lenses do not compound the deficiencies of available film.
(B) is necessary because if it were not true — if differences in lens resolution DO compound (in other words, make worse) the deficiencies of film, then this is a reason lens resolution might make a practical difference. So the author must assume that differences in lens resolution do NOT make worse the deficiencies of film in order to conclude that there’s no practical difference between different lens resolutions.
C
Variations in the method used to process the film do not have any significant effect on the film’s resolution.
(C) doesn’t say anything about camera lens resolution. The author doesn’t have to assume anything about film resolution except as it relates to camera lens resolution. If variations in processing film do have large effects on film’s resolution, that doesn’t undermine the author’s point, which is that camera lens project more detail than any film can capture in an image, and that this is why lens resolution differences don’t matter.
D
Flawless photographic technique is needed to achieve the maximum image resolution possible with the materials and equipment being used.
The author asserts that modern lenses project far more detail onto film than any film can reproduce. But there’s no indication the author believes we “need” to use “flawless” technique achieve this level of detail or any other level of detail.
E
The only factors important in determining the degree of detail reproduced in the final photographic print are the resolution of the camera’s lens and the resolution of the film.
(E) isn’t necessary, because even if there are other factors important to the level of detail in the final print (such as the quality of a printer, perhaps), the author’s reasoning involves only the relationship between lens resolution and the detail reproducible on a developed image. After we get the image, there might be further factors that affect the detail of a printed image, but the author’s argument doesn’t relate to this stage.
Summarize Argument: Phenomenon-Hypothesis
The resident concludes that closing the recreation center would make the situation unacceptable. He supports this by claiming that recreation facilities are a neighborhood necessity, and pointing out that the neighborhood already had more residents per center than any other neighborhood in the city.
Notable Assumptions
The resident assumes that the recreation center was being used enough to justify remaining open. This also means that he assumes a recreation center remaining open should depend on how well-used that center is. The resident also assumes that recreation center in a nearby neighborhood wouldn’t be able to provide adequate access to recreation facilities.
A
A large number of the neighborhood’s residents are unable to travel outside their locality to gain access to recreational facilities.
This means that another recreation center wouldn’t provide adequate access to recreation facilities for neighborhood residents. This supports the resident’s argument that closing the recreation center is unacceptable.
B
Children, the main users of recreational facilities, make up a disproportionately small segment of the neighborhood’s population.
True, the neighborhood has more residents per recreation center than any other neighborhood. But most people who use recreation centers are children, and this neighborhood has very few chilren.
C
Often the recreation center in the neighborhood is open but not being used.
Even when the recreation center is open, people choose not to go. This weakens the resident’s claim that the recreation center is a neighborhood necessity.
D
Programs that are routinely filled at other recreation centers must be canceled at the neighborhood’s recreation center due to lack of interest.
Like (C), this says that people simply aren’t using the recreation center. It weakens the resident’s claim that the recreation center is a neighborhood necessity.
E
As people become more involved in computers and computer games, recreation centers are becoming increasingly less important.
People would rather play video games than go to the recreation center. It simply won’t be used enough to remain open.