答案解析
Prep2012-Pack1-CR-071 VCR014016 Hard
Reasoning
What conclusion would the statements about utilities’ coal-related expenses support? Low-quality coal costs less per ton, but burning low-quality coal generates electricity less efficiently and produces more ash, which utilities must pay an increasing amount to dispose of. It's unclear whether overall coal purchasing costs are lower with low-quality or high-quality coal, since the lower price per ton of the former may counterbalance the need to buy more tons to generate the same amount of electricity. Although ash disposal is becoming more expensive, we are not told how that expense compares to those of the other factors mentioned; it may be negligible.
A. Correct. The information presented does not clearly support a conclusion about whether it's economically beneficial for coal-burning utilities to minimize their coal-purchasing costs. Therefore, utilities relying solely on this information cannot be assured that it is.
B. Since high-quality coal burns more efficiently, the utilities can buy less of it to generate the same amount of electricity, potentially compensating for its greater expense per ton.
C. The transportation costs per ton are probably about the same for low-quality coal as for high-quality coal. Therefore, they are probably a greater proportion of the cost per delivered ton of low-quality coal.
D. We are given no information about whether the cost to dispose of a ton of coal ash depends on the type of coal burned to generate that ash.
E. Even in the regions where coal-ash disposal is least expensive, it may still be expensive enough to encourage utilities to mine and burn more high-quality coal and thus generate less ash.
The correct answer is A.
Prep2012-Pack1-CR-072 VCR006014 Hard
Reasoning
What would support the conclusion that hourly wages are higher at Yorco than at Zortech? If both companies employ the same number of full-time hourly wage workers, but Yorco spends more on wages for those workers, then on average, wages per full-time hourly wage worker are higher at Yorco than at Zortech. Consequently, the workers at Yorco must either get paid more per hour or else work longer hours than the workers at Zortech. Thus, if the workers at Yorco do not work longer hours, they must get paid more per hour. Therefore, to support the conclusion that the Yorco workers get paid more per hour, look for an answer option suggesting that they do not work longer hours.
A. The argument is just about wages, not about other benefits.
B. The argument is just about wages, not about the skills used to earn those wages.
C. The argument is not about employees other than full-time hourly wage workers.
D. Correct. This suggests that full-time hourly wage workers at Yorco do not work longer hours than those at Zortech. Therefore, it supports the argument's conclusion as explained above.
E. Even if the highest hourly wages are higher at Yorco, the average hourly wages may be the same or lower—contrary to what the argument claims.
The correct answer is D.
Prep2012-Pack1-CR-073 VCR006119 Hard
Reasoning
What piece of information must be an implicit part of the argument in order for the argument to succeed? The proposed method assumes that the oceans were initially salt-free and that the amount of salt entering them in the past century was roughly the average amount that has entered them per century since they formed. Since the method relies solely on the rate at which rivers have deposited salt in the oceans, it also assumes that all or almost all salt in the oceans was deposited by rivers. Therefore, look for an answer option that follows from these assumptions.
A. Correct. Since the argument assumes that the amount of salt entering the oceans in the past century has been typical and that rivers deposited all or almost all the salt in the oceans, it must also assume that the amount of salt rivers have deposited in the oceans in the past century has been typical.
B. The argument assumes that the rate at which rivers have collectively deposited salt into the oceans in the past century has been typical, but different rivers could still have different salt levels from each other.
C. As explained above, the argument assumes that all or almost all salt in the oceans came there from rivers, not out of the ocean floor.
D. D Provided that the proposed method is accurate, there is no need for the argument to assume that it is also "superior" to any other methods—some of which might be not only accurate but also superior in virtue of being easier, cheaper, or more elegant.
E. E The proposed method may yield an accurate result even if biological activity uses up some of the ocean's salts, as long as the rate at which that activity has occurred in the past century has been roughly the average rate since the oceans formed.
The correct answer is A.
