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
The author concludes that every mother bat is able to recognize the call of her pup. As evidence, the author states that a bat’s calls are the only means of finding one another, and that a bat pup cannot distinguish calls between adult bats.
Describe Method of Reasoning
The author concludes that a mother bat must be able to recognize the call of her pup by eliminating the possibility of a bat pup recognizing the call of a mother bat.
A
derive a general conclusion about all members of a group from facts known about representative members of that group
The author does not provide facts about representative members of a group. While the author’s conclusion is a general conclusion applying to all mother bats, the author’s premises do not include facts about a specific set of mother bats.
B
establish the validity of one explanation for a phenomenon by excluding alternative explanations
The alternative explanation the author excludes is the possibility of a bat pup recognizing its mother’s call. Since this is not a possibility, the author concludes that the other possibility of a mother bat recognizing its pup’s call is a valid explanation.
C
support, by describing a suitable mechanism, the hypothesis that a certain phenomenon can occur
The author does not describe how mother bats are able to recognize a pup’s call. Rather, the author states this phenomenon as a matter of fact.
D
conclude that members of two groups are likely to share a certain ability because of other characteristics they share
The author only addresses and comes to a conclusion about one group of animals. The author does not make comparisons between bats and any other animal.
E
demonstrate that a general rule applies in a particular case
The author does not provide a particular case that illustrates the conclusion. Rather, the author’s argument is stated generally and theoretically.
Summarize Argument: Counter-Position
In response to the claim that a mixture is an effective cold remedy, the cold sufferer concludes that the mixture is obviously not effective. As evidence, the cold sufferer points out that if the mixture was an effective remedy, then most people with colds would use it. However many people with colds do not use the mixture.
Describe Method of Reasoning
The cold sufferer counters a position held by others. He does this first by establishing a conditional relationship between the mixture and its use: if the mixture was an effective remedy, then most people with colds would use it. However, the cold sufferer denies the necessary condition of this relationship by stating many people with colds do not use the mixture, therefore the sufficient condition of the mixture being an effective remedy must also be denied.
A
finding a claim to be false on the grounds that it would if true have consequences that are false
The claim the cold sufferer finds false is the claim that the mixture is an effective remedy. The grounds the cold sufferer uses is the conditional relationship if the mixture is effective, then most people with colds would use it. However, this necessary condition is false.
B
accepting a claim on the basis of public opinion of the claim
The cold sufferer does not state whether the public’s opinion is that the mixture is an ineffective remedy. We cannot assume that just because many people with colds do not use the mixture that those people believe the mixture is ineffective.
C
showing that conditions necessary to establish the truth of a claim are met
The cold sufferer points out that the necessary condition for determining whether the mixture is an effective remedy is false: it is not the case that most people with colds use the mixture.
D
basing a generalization on a representative group of instances
The cold sufferer does not mention representative instances. Rather, the cold sufferer’s argument stays in general, theoretical territory.
E
showing that a measure claimed to be effective in achieving a certain effect would actually make achieving the effect more difficult
The cold sufferer does not claim that the mixture would make it more difficult for people with colds to recover. Rather, the cold sufferer is only arguing that the mixture is ineffective.