[Problem Solving]
试题详情
题目：
In a certain sequence, the term xn is given by the formula for all n ≥ 2. If x0 = 3 and x1 = 2, what is the value of x3 ?
选项:
A、2.5
B、3.125
C、4
D、5
E、6.75
答案:
C
问答
1答疑
1答疑
[Critical Reasoning]
试题详情
题目：
Which of the following most logically completes the passage?
Leaf beetles damage willow trees by stripping away their leaves, but a combination of parasites and predators generally keeps populations of these beetles in check. Researchers have found that severe air pollution results in reduced predator populations. The parasites, by contrast, are not adversely affected by pollution; nevertheless, the researchers' discovery probably does explain why leaf beetles cause particularly severe damage to willows in areas with severe air pollution, since __________.
选项:
A、
A. neither the predators nor the parasites of leaf beetles themselves attack willow trees
B、
B. the parasites that attack leaf beetles actually tend to be more prevalent in areas with severe air pollution than they are elsewhere
C、
C. the damage caused by leaf beetles is usually not enough to kill a willow tree outright
D、
D. where air pollution is not especially severe, predators have much more impact on leaf-beetle populations than parasites do
E、
E. willows often grow in areas where air pollution is especially severe
答案:
D
1答疑
[Data Sufficiency]
试题详情
题目：
Is xy < 6 ?
- x < 3 and y < 2.
- and y 2 < 64.
选项:
A、Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B、Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C、BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D、EACH statement ALONE is sufficient.
E、Statements (1) and (2) TOGETHER are NOT sufficient.
答案:
B
1答疑
[Critical Reasoning]
试题详情
题目：
To prevent a newly built dam on the Chiff River from blocking the route of fish migrating to breeding grounds upstream, the dam includes a fish pass, a mechanism designed to allow fish through the dam. Before the construction of the dam and fish pass, several thousand fish a day swam upriver during spawning season. But in the first season after the project's completion, only 300 per day made the journey. Clearly, the fish pass is defective.
Which of the following, if true, most seriously weakens the argument?
选项:
A、
A. Fish that have migrated to the upstream breeding grounds do not return down the Chiff River again.
B、
B. On other rivers in the region, the construction of dams with fish passes has led to only small decreases in the number of fish migrating upstream.
C、
C. The construction of the dam stirred up potentially toxic river sediments that were carried downstream.
D、
D. Populations of migratory fish in the Chiff River have been declining slightly over the last 20 years.
E、
E. During spawning season, the dam releases sufficient water for migratory fish below the dam to swim upstream.
答案:
C
1答疑
[Critical Reasoning]
试题详情
题目：
Which of the following, if true, most logically completes the politician's argument?
United States politician: Although the amount of United States goods shipped to Mexico doubled in the year after tariffs on trade between the two countries were reduced, it does not follow that the reduction in tariffs caused the sales of United States goods to companies and consumers in Mexico to double that year, because __________.
选项:
A、many of the United States companies that produced goods that year had competitors based in Mexico that had long produced the same kind of goods
B、most of the increase in goods shipped by United States companies to Mexico was in parts shipped to the companies’ newly relocated subsidiaries for assembly and subsequent shipment back to the United States
C、marketing goods to a previously unavailable group of consumers is most successful when advertising specifically targets those consumers, but developing such advertising often takes longer than a year
D、the amount of Mexican goods shipped to the United States remained the same as it had been before the tariff reductions
E、there was no significant change in the employment rate in either of the countries that year
答案:
B
1答疑
[Data Sufficiency]
试题详情
题目：
For each landscaping job that takes more than 4 hours, a certain contractor charges a total of r dollars for the first 4 hours plus 0.2r dollars for each additional hour or fraction of an hour, where 
. Did a particular landscaping job take more than 10 hours?
. Did a particular landscaping job take more than 10 hours?(1) The contractor charged a total of $288 for the job.
(2) The contractor charged a total of 2.4r dollars for the job.
选项:
答案:
B
1答疑
[Multi-Source Reasoning]
试题详情
文章：
Height-for-age standards
The World Health Organization (WHO) has produced a comprehensive set of growth standards for children. These standards are based on studies of children living in 6 nations on 5 continents under optimal conditions with respect to health and nutrition. The table displays the percentile distribution of height, in centimeters, at 3-month intervals, for boys ages 2 through 5 according to the WHO model. In a model population—a large population of boys ages 2 through 5 that conforms to the WHO growth standards—for n = 3.15, 50. 85. and 97, the nth percentile in height for a given age is the unique height among boys of that age that is greater than or equal to n percent, and less than or equal to (100 - n) percent, of heights of boys of that age.
Weight-for-height standards
The graph shows the percentile distribution of weight, in kilograms, for heights from 80 cm to 120 cm. for boys ages 2 through 5, according to the WHO model. In a model population, for n = 3,15,50,85, and 97. the nth percentile in weight for a given height is the unique weight among boys of that height that is greater than or equal to n percent, and less than or equal to (100 - n) percent, of weights of boys of that age.
题目：
14. For each of the following statements, select Yes if the statements must be true of a boy select at random from a model population. Otherwise, select No.
选项:
A、If his age is greater than 3 years 3 mouths, the probability that his height is at least 98.0 cm is greater than 50%.
B、If he is at least 105 cm tall, the probability that his weight is 14.0 kg is no greater than 3%.
C、If he is 114 cm tall, he is taller than at least 85% of boys his age.
答案:
A A B
1答疑
[Data Sufficiency]
试题详情
题目：
In the xy-plane, what is the x-intercept of a certain line?
(1) The line passes through the point (0,2).
(2) The y-intercept of the line is 2.
选项:
答案:
E
1答疑
[Critical Reasoning]
试题详情
题目：
United Lumber will use trees from its forests for two products. The tree trunks will be used for lumber and the branches converted into wood chips to make fiberboard. The cost of this conversion would be the same whether done at the logging site, where the trees are debranched, or at United's factory. However, wood chips occupy less than half the volume of the branches from which they are made.
The information given, if accurate, most strongly supports which of the following?
The information given, if accurate, most strongly supports which of the following?
选项:
A、Converting the branches into wood chips at the logging site would require transporting a fully assembled wood-chipping machine to and from the site.
B、It would be more economical to debranch the trees at the factory where the fiberboard is manufactured.
C、The debranching of trees and the conversion of the branches into chips are the only stages in the processing of branches that it would be in United's economic advantage to perform at the logging site.
D、Transportation costs from the logging site to the factory that are determined by volume of cargo would be lower if the conversion into chips is done at the logging site rather than at the factory.
E、In the wood-processing industry, branches are used only for the production of wood chips for fiberboard.
答案:
D
1答疑
[Problem Solving]
试题详情
题目：
Enrollment in City College in 1980 was 83⅓ percent of enrollment in 1990. What was the percent increase in the college's enrollment from 1980 to 1990?
选项:
A、10%
B、16⅔%
C、20%
D、25%
E、183⅓%
答案:
C
0评分
1933浏览
[Undefined]
Art historian: Unlike many artistic traditions that sought to depict plants native to the local area in a seasonally appropriate way (for example, depicting scenes of spring with the plants in the appropriate stages of development for that season), seventeenth-century Dutch artists specializing in flower paintings almost exclusively chose to depict exotic species of flowers from outside the local area. Painting such species was worthwhile primarily because the art-buying public had developed a strong preference for images of the exotic. The great botanical centers of the time gave the artists direct access to such flowers, which the artists would freely combine in a single painting, regardless of whether the combined species occurred together in the wild, and depicted each in full bloom, regardless of whether those species bloomed at the same time in nature.
Statement: The art historian makes the point that the species of flowers these Dutch artists chose to paint were 1 largely because the species were 2 .
Select for 1 and for 2 the options that complete the statement so that it is most strongly supported by the information provided. Make only two selections, one in each column.
Statement: The art historian makes the point that the species of flowers these Dutch artists chose to paint were 1 largely because the species were 2 .
Select for 1 and for 2 the options that complete the statement so that it is most strongly supported by the information provided. Make only two selections, one in each column.
我选的CE，和EC有什么区别？怎么选出EC的？
0评分
5023浏览
[Undefined]
An unusually severe winter occurred in Europe after the continent was blanketed by a blue haze resulting from the eruption of the Laki Volcano in the European republic of Iceland in the summer of 1984. Thus, it is evident that major eruptions cause the atmosphere to become cooler than it would be otherwise.
Which of the following statements, if true, most seriously weakens the argument above?
C选项为什么就不会有张冠李戴的问题呢，1984和1982的气候情况能一样吗，C里的火山就可以试用于原文的火山吗
0评分
5707浏览
[Undefined]
The rate of a certain chemical reaction is directly proportional to the square of the concentration of chemical A present and inversely proportional to the concentration of chemical B present. If the concentration of chemical B is increased by 100 percent, which of the following is closest to the percent change in the concentration of chemical A required to keep the reaction rate unchanged?
为什么这个题一定是相乘不能是相加呢？y=k1A方-k2B （k1,k2大于0 ），也满足题目说的与A方成正比与B成反比啊？但是这道题只有相乘的情况才能选出正确答案
0评分
1912浏览
[Undefined]
Tiger beetles are such fast runners that they can capture virtually any nonflying insect. However, when running toward an insect, the beetles intermittently stop, and then, a moment later, resume their attack. Perhaps they cannot maintain their pace and must pause for a moment's rest; but an alternative hypothesis is that while running tiger beetles are unable to process the resulting rapidly changing visual information, and so quickly go blind and stop.
Which of the following, if discovered in experiments using artificially moved prey insects, would support one of the two hypotheses and undermine the other?
答案C是怎么支持一个猜想又削弱另一个猜想的？
0评分
4131浏览
[GWD]
The author of the passage implies that which of the following is a possible partial explanation for acquisition behavior during the 1970's and 1980's?
请解释这道题为什么不选C或E，除了正确选项B，我认为文中也正确地提到了这两个选项可以解释acquisition behavior during 1970s and 80s
0评分
2898浏览
0评分
1915浏览
[Undefined]
Club X has more than 10 but fewer than 40 members. Sometimes the members sit at tables with 3 members at one table and 4 members at each of the other tables, and sometimes they sit at tables with 3 members at one table and 5 members at each of the other tables. If they sit at tables with 6 members at each table except one and fewer than 6 members at that one table, how many members will be at the table that has fewer than 6 members?
提问小梅老师 这道题求讲一下 我没什么思路 带入数字得的是3
0评分
2003浏览
[Undefined]
A photography dealer ordered 60 Model X cameras to be sold for $250 each, which represents a 20 percent markup over the dealer's initial cost for each camera. Of the cameras ordered, 6 were never sold and were returned to the manufacturer for a refund of 50 percent of the dealer's initial cost. What was the dealer's approximate profit or loss as a percent of the dealer's initial cost for the 60 cameras?
请问小梅老师 这道题讲讲一下 我算的是19% 原来成本是200每个 亏了6个 每个亏100. 最后得不出答案
0评分
427117浏览
0评分
434255浏览
