GMAT逻辑考前练习题目及答案解析分享【3 Day】

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  　　1. Roses always provide a stunning display of color, but only those flowers that smell sweet are worth growing in a garden. Some roses have no scent.

  　　Which one the following conclusions can be properly drawn from the passage?

  　　(A) Some flowers which provide a stunning display of color are not worth growing in a garden.

  　　(B) All flowers with no scent provide a stunning display of color.

  　　(C) Some flowers which are worth growing in a garden have no scent.

  　　(D) Some roses which smell sweet are not worth growing in a garden.

  　　(E) No sweet-smelling flower is worth growing in a garden unless it provides a stunning display of color.

  　　2. The use of money causes a civilization to decline. That this is true is shown by the way the troubles of Western civilization began with the invention of money. While real money (gold and silver) is bad enough, imitation money (paper money) is a horror. The decline of Western civilization exactly parallels the increasing use of money—both real money and worthless paper money—as a substitute for things of intrinsic value.

  　　Which one of the following, if true, could contribute most to a refutation of the argument?

  　　(A) People prefer using money to having a system in which goods are bartered for other goods of equal intrinsic value.

  　　(B) Eastern cultures have used money, and Eastern civilizations have not declined.

  　　(C) The use of paper money encourages disregard for the value of work because the money itself has no intrinsic value.

  　　(D) The rate of exchange between gold and paper money has fluctuated greatly in Western civilization.

  　　(E) Some employers exchange goods for their employees’ services in order to avoid the exchange of money.

  　　3. Fire ants from Brazil now infest the southern United States. Unlike queen fire ants in Brazil, two queens in the United States share a nest. Ants from these nests are more aggressive than those from single-queen nests. By destroying virtually all insects in the nest area, these aggressive ants gain sole access to food sources, and the ant population skyrockets. Since certain predator insects in Brazil limit the fire-ant population there, importing such predator insects into the United States would be of overall benefit to the environment by stopping the increase of the fire-ant population in the United States.

  　　Each of the following is an assumption made in the argument EXCEPT:

  　　(A) The imported insects would not prove more damaging to the environment in the United States than are the fire ants themselves.

  　　(B) The predator insects from Brazil could survive in the ecological environment found in the United States.

  　　(C) The especially aggressive fire ants from the two-queen nests would not be able to destroy the Brazilian predator insects.

  　　(D) The predator insects would stop the increase of the ant population before the ants spread to states that are farther north.

  　　(E) The rate of increase of the fire-ant population would not exceed the rate at which the predator insects could kill the ants.

  　　4. In an attempt to counter complaints that a certain pesticide is potentially hazardous to humans if absorbed into edible plants, the pesticide manufacturer has advertised that “ounce for ounce, the active ingredient in this pesticide is less toxic than the active ingredient in mouthwash.”

  　　Which one of the following, if true, indicates a weakness in the manufacturer’s argument?

  　　(A) The ounce-for-ounce toxicity of the active ingredient in mouthwash is less than that of most products meant for external use by humans, such as nail polish or other cosmetics.

  　　(B) The quantity of toxins humans ingest by consuming plants treated with the pesticide is, on average, much higher than the quantity of toxins humans ingest by using mouthwash.

  　　(C) The container in which the pesticide is packaged clearly identifies the toxic ingredients and carries warnings about their potential danger to humans.

  　　(D) On average, the toxins present in the pesticide take longer than the toxins present in mouthwash to reach harmful levels in the human body.

  　　(E) Since the government began to regulate the pesticide industry over ten years ago, there has been a growing awareness of the dangers of toxins used in pesticides.

  　　Questions 5-6

  　　Four randomly chosen market research companies each produced population estimated for three middle-sized cities; the estimates of each company were then compared with those of the other companies. Two of the cities had relatively stable populations, and for them estimates of current population and of projected population in five years varied little from company to company. However, for the third city, which was growing rapidly, estimates varied greatly from company to company.

  　　5. The passage provides the most support for which one of the following?

  　　(A) It is more difficult to estimate the population of middle-sized cities than of smaller cities.

  　　(B) Population estimates for rapidly growing cities can be accurate enough to be useful for marketing.

  　　(C) The rate of change in population of rapidly growing cities does not fluctuate.

  　　(D) The market research companies are likely to be equally reliable in estimating the population of stable cities.

  　　(E) Estimates of city’s future population are likely to be more accurate than are estimates of that city’s current population.

  　　6. Which one of the following, if true, would best help explain why estimates of the current population of the rapidly growing city varied more than did current population estimates for the two other cities?

  　　(A) Population changes over time are more uniform from one district to another in the rapidly growing city than in the two other cities.

  　　(B) The population of the rapidly growing city is increasing largely as a result of a high birth rate.

  　　(C) The population of the rapidly growing city has a lower average age than the populations of either of the two other cities.

  　　(D) All population estimates of the rapidly growing city were produced first by estimating the current populations of the city’s districts and then by adding those estimates.

  　　(E) Whereas the companies used different methods for estimating the current population of the rapidly growing city, the companies used the same method for the two other cities.

  　　7. Head injury is the most serious type of injury sustained in motorcycle accidents. The average cost to taxpayers for medical care for nonhelmeted motorcycle-accident victims is twice that for their helmeted counterparts. Jurisdictions that have enacted motorcycle-helmet laws have reduced the incidence and severity of accident-related head injuries, thereby reducing the cost to taxpayers. Therefore, to achieve similar cost reductions, other jurisdictions should enact motorcycle-helmet laws. For the same reason jurisdictions should also require helmets for horseback riders, since horseback-riding accidents are even more likely to cause serious head injury than motorcycle accidents are.

  　　Which one of the following is an assumption upon which the author’s conclusion concerning helmets for horseback riders depend?

  　　(A) Medical care for victims of horseback-riding accidents is financial drain on tax funds.

  　　(B) The higher rate of serious head injury suffered by victims of horseback-riding accidents is due to the difference in size between horses and motorcycles.

  　　(C) The medical costs associated with treating head injuries are higher than those for other types of injury.

  　　(D) Most fatalities resulting from horseback-riding and motorcycle accidents could have been prevented if the victims had been wearing helmets.

  　　(E) When deciding whether to enact helmet laws for motorcyclists and horseback riders, the jurisdiction’s primary concerns is the safety of its citizens.

  　　8. The senator has long held to the general principle that no true work of art is obscene, and thus that there is no conflict between the need to encourage free artistic expression and the need to protect the sensibilities of the public from obscenity. When well-known works generally viewed as obscene are cited as possible counterexamples, the senator justifies accepting the principle by saying that if these works really are obscene then they cannot be works of art.

  　　The senator’s reasoning contains which one of the following errors?

  　　(A) It seeks to persuade by emotional rather than intellectual means.

  　　(B) It contains an implicit contradiction.

  　　(C) It relies on an assertion of the senator’s authority.

  　　(D) It assumes what it seeks to establish.

  　　(E) It attempts to justify a position by appeal to an irrelevant consideration.

  　　9. Until he was dismissed amid great controversy, Hastings was considered one of the greatest intelligence agents of all time. It is clear that if his dismissal was justified, then Hastings was either incompetent or else disloyal. Soon after the dismissal, however, it was shown that he had never been incompetent. Thus, one is forced to conclude that Hastings must have been disloyal.

  　　Which one of the following states an assumption upon which the argument depends?

  　　(A) Hastings’s dismissal was justified.

  　　(B) Hastings was a high-ranking intelligence officer.

  　　(C) The dismissal of anyone who was disloyal would be justified.

  　　(D) Anyone whose dismissal was justified was disloyal.

  　　(E) If someone was disloyal or incompetent, then his dismissal was justified.

  　　10. Anyone who fails to answer a patient’s questions cannot be a competent physician. That is why I feel confident about my physician’s competence: she carefully answers every one of my questions, no matter how trivial.

  　　Which one of the following most closely parallels the flawed reasoning in the argument above?

  　　(A) Anyone who grows up in a large family is accustomed to making compromises. Meredith is accustomed to making compromises, so she might have grown up in a large family.

  　　(B) Anyone who is not in favor of this proposal is ill informed on the issue. Jeanne opposes the proposal, so she is ill informed on the issue.

  　　(C) No one who likes music misses a performance of the symphony. Paul likes music, yet last week he missed a performance of the symphony.

  　　(D) Anyone who works two or more jobs is unable to find a balance between professional and personal life. Maggie has only one job, so she can find a balance between her professional and personal life.

  　　(E) No one who is hot-tempered and strong-willed will succeed in this business. Jeremy is strong-willed, so he will not succeed in this business.

  　　参考答案：

  　　1. A 2. B 3. D 4. B 5. D

  　　6. E 7. A 8. D 9. A 10. D

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