GMAT逻辑复习资料-逻辑大全分类-Assumption

大豆

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大全-4-17.        One state adds a 7 percent sales tax to the price of most products purchased within its jurisdiction. This tax, therefore, if viewed as tax on income, has the reverse effect of the federal income tax : the lower the income, the higher the annual percentage rate at which the income is taxed.
结论：收入越低，每年税额所占收入的比例越高。
Federal tax works in a way that the higher the income is, the higher the tax rate is. The sales tax is opposite: the lower the income, the higher the tax rate (because the 7% is on the goods purchased and steady).
题目意思：州税增加了购物税，如果这也算做收入税的一部分，就违反了联邦的收入税方针－－收入少，收入税就应该少．而这样增加购物税的结果就成了收入越少，收入税所占的比例越高。
收入税比率=交税收入/总收入
总收入少，交税收入相同的情况下（即居民花在需要交税的商品上的钱在各收入阶层是相等的，就是说大款和叫花子花同样多的钱买这些商品），收入税比率才会大。
The conclusion above would be properly drawn if which of the following were assumed as a premise?
(A) The amount of money citizens spend on products subject to the state tax tends to be equal across income levels.
(B) The federal income tax favors citizens with high incomes, whereas the state sales tax favors citizens with low incomes.
(C) Citizens with low annual incomes can afford to pay a relatively higher percentage of their incomes in state sales tax, since their federal income tax is relatively low.
(D) The lower a state’s sales tax, the more it will tend to redistribute income from the more affluent citizens to the rest of society.（A）
(E) Citizens who fail to earn federally taxable income are also exempt from the state sales tax.

大豆

大全-2-20.        Which of the following inferences about the consequences of instituting the new tests is best supported by the passage above?
(A) The incidence of new cases of NANB hepatitis is likely to go up by 10 percent.
(B) Donations made by patients specifically for their own use are likely to become less frequent.
(C) The demand for blood from blood banks is likely to fluctuate more strongly.
(D) The blood supplies available from blood banks are likely to go down.
测试可以检查出不合适的献血者，那么合适的献血者就少了，可利用的血液也自然就少了。
(E) The number of prospective first-time donors is likely to go up by 5 percent.

大豆

大全-2-19.        The argument above depends on which of the following assumptions?
(A) Donors carrying NANB hepatitis do not, in a large percentage of cases, carry other infections for which reliable screening tests are routinely performed.
(B) Donors carrying NANB hepatitis do not, in a large percentage of cases, develop the disease themselves at any point.
(C) The estimate of the number of donors who would be disqualified by tests for NANB hepatitis is an underestimate.
(D) The incidence of NANB hepatitis is lower among the potential blood donors than it is in the population at large.
(E) The donors who will still supply NANB-contaminated blood will donate blood at the average frequency for all donors.

大豆

大全-2-14.        A recent survey of all auto accident victims in Dole County found that, of the severely injured drivers and front-seat passengers, 80 percent were not wearing seat belts at the time of their accidents. This indicates that, by wearing seat belts, drivers and front-seat passengers can greatly reduce their risk of being severely injured if they are in an auto accident.
The conclusion above is not properly drawn unless which of the following is true?
(A) Of all the drivers and front-seat passengers in the survey, more than 20 percent were wearing seat belts at the time of their accidents.
调查的人中，20%是在事故中系了安全带的。只有这样，才能说明系安全带起了作用。
(B) Considerably more than 20 percent of drivers and front-seat passengers in Dole County always wear seat belts when traveling by car.范围太广，原文只限制在事故调查中的司机和乘客。
(C) More drivers and front-seat passengers in the survey than rear-seat passengers were very severely injured.
(D) More than half of the drivers and front-seat passengers in the survey were not wearing seat belts at the time of their accidents.
(E) Most of the auto accidents reported to police in Dole County do not involve any serious injury.
Questions 19-20 are based on the following.
Blood banks will shortly start to screen all donors for NANB hepatitis. Although the new screening tests are estimated to disqualify up to 5 percent of all prospective blood donors, they will still miss two-thirds of donors carrying NANB hepatitis. Therefore, about 10 percent of actual donors will still supply NANB-contaminated blood.
测试可以筛出5%不合格的，但仍有2/3不合格的筛不出来，也就是5%只占1/3，总共有15%不合适的，还有10%没筛出来。A的意思是这10%的人没有别的测试可检查出来的毛病（如果有，肯定也筛出来了，就不会有10%带NANB的人在里面了，结论就不成立）。排除他因。

大豆

大全-3-11.        An electric-power company gained greater profits and provided electricity to consumers at lower rates per unit of electricity by building larger-capacity more efficient plants and by stimulating greater use of electricity within its area. To continue these financial trends, the company planned to replace an old plant by a plant with triple the capacity of its largest plant.
The company’s plan as described above assumed each of the following EXCEPT:
(A) Demand for electricity within the company’s area of service would increase in the future.
(B) Expenses would not rise beyond the level that could be compensated for by efficiency or volume of operation, or both.
(C) The planned plant would be sufficiently reliable in service to contribute a net financial benefit to the company as a whole.
(D) Safety measures to be instituted for the new plant would be the same as those for the plant it would replace.
(E) The tripling of capacity would not result in insuperable technological obstacles to efficiency.

大豆

大全-3-5.        A weapons-smuggling incident recently took place in country Y. We all know that Y is a closed society. So Y’s government must have known about the weapons.
Which of the following is an assumption that would make the conclusion above logically correct?
(A) If a government knows about a particular weapons-smuggling incident, it must have intended to use the weapons for its own purposes.
(B) If a government claims that it knew nothing about a particular weapons-smuggling incident, it must have known everything about it.
(C) If a government does not permit weapons to enter a country, it is a closed society.
(D) If a country is a closed society, its government has a large contingent of armed guards patrolling its borders.
(E) If a country is a closed society, its government has knowledge about everything that occurs in the country.

大豆

大全-3-1.        Child’s World, a chain of toy stores, has relied on a “supermarket concept” of computerized inventory control and customer self-service to eliminate the category of sales clerks from its force of employees. It now plans to employ the same concept in selling children’s clothes.
The plan of Child’s World assumes that
(A) supermarkets will not also be selling children’s clothes in the same manner
(B) personal service by sales personnel is not required for selling children’s clothes successfully
(C) the same kind of computers will be used in inventory control for both clothes and toys at Child’s World
(D) a self-service plan cannot be employed without computerized inventory control
(E) sales clerks are the only employees of Child’s World who could be assigned tasks related to inventory control

大豆

大全-10-14.        A company’s personnel director surveyed employees about their satisfaction with the company’s system for awarding employee performance ratings. The survey data indicated that employees who received high ratings were very satisfied with the system. The personnel director concluded from these data that the company’s best-performing employees liked the system.
The personnel director’s conclusion assumes which of the following?
公司人事主管调查了员工对公司员工表现评级奖励系统的满意程度。调查数据表明得到高级别的员工非常满意该系统。人事主管得出结论：公司表现最好的员工喜欢该系统。
注意GAP：
前提是employees who received high ratings对系统满意，
而结论是best-performing employees喜欢该系统。
(A) No other performance rating system is as good as the current system.
(B) The company’s best-performing employees received high ratings.
(C) Employees who received low ratings were dissatisfied with the system.
(D) Employees who receive high ratings from a performance-rating system will like that system.
(E) The company’s best-performing employees were motivated to perform well by the knowledge that they would receive performance ratings.

大豆

费费CR:
21. Historian: We can learn about the medical history of individuals through chemical analysis of their hair. It is likely, for example, that Isaac Newton’s psychological problems were due to mercury poisoning; traces of mercury were found in his hair. Analysis is now being done on a lock of Beethoven’s hair. Although no convincing argument has shown that Beethoven ever had a venereal disease, some people hypothesize that venereal disease caused his deafness. Since mercury was commonly ingested in Beethoven’s time to treat venereal disease, if researchers find a trace of mercury in his hair, we can conclude that this hypothesis is correct.
Which one of the following is an assumption on which the historian’s argument depends?
(A) None of the mercury introduced into the body can be eliminated.
(B) Some people in Beethoven’s time did not ingest mercury.
(C) Mercury is an effective treatment for venereal disease.
(D) Mercury poisoning can cause deafness in people with venereal disease.
(E) Beethoven suffered from psychological problems of the same severity as Newton’s.
Lawyer关于取非的解释：
取非实际是句子的主项和谓项取非。谓项已解决，是取非变不是，不是取非变是。主项的取非可用画圈法去理解。圈内为主项，则圈外为取非项。如本题，圈内为SOME，则圈外为SOME之外，可理解为：大多数。B项取非后为：那个时候，多数人吃M。如果这样，原文的结论就推不出。
对命题取非不是找命题的否命题。
“部分A是B”的非命题是“全部A都不是B”。这是逻辑上的对当关系。
从为何命题取非的根源上可找到答案
1。ASSUMPTION是结论成立的必要条件，必要条件不成立（假命题），则结论也不成立。这就是为何ASSUMPTION的正确选项取非，结论必不成立的原因。一句话，选项取非的含义就是找选项的假命题（或者叫假判断）（因为原文是假设选项是真）
2。从逻辑上讲，假命题和真命题是矛盾关系（四种对当关系中的一种）。逻辑有两种矛盾关系：全称肯定判断和特称肯定是矛盾关系，全称否定和特称肯定是矛盾关系。
3。该文中，B选项为特称否定命题，其矛盾关系的命题为：EVERYONE DO（全称肯定）
4。B取非为：那时候，每个人都吃贡。如果这样，则结论不成立。

大豆

大全-10-13.        Exports of United States wood pulp will rise considerably during this year. The reason for the rise is that the falling value of the dollar will make it cheaper for paper manufacturers in Japan and Western Europe to buy American wood pulp than to get it from any other source.
Which of the following is an assumption made in drawing the conclusion above?
美元贬值会使日本和西欧造纸商购买美国木桨而不是从其它渠道购买，所以美国木桨出口量会大幅上升。
(A) Factory output of paper products in Japan and Western Europe will increase sharply during this year.
(B) The quality of the wood pulp produced in the United States would be adequate for the purposes of Japanese and Western European paper manufacturers.
(C) Paper manufacturers in Japan and Western Europe would prefer to use wood pulp produced in the United States if cost were not a factor.
如果不考虑价格因素，日本和西欧造纸商会比较喜欢美国木桨。
关键对原文逻辑的把握。原文的逻辑是：美国货便宜，所以日本和西欧会购买。B说美国货质量必须满足要求。将它取非后，结论就推不出了（不合要求，再便宜也没用）。C的核心是J，WE更爱美国货。J，WE买美国货是因为便宜，更爱不爱无关。C很容易混，但方向偏了。其实原文只要能搭起便宜就会买的桥就可以。
取非的的方法，当选项的取非问题较复杂时，还是慎用，会TRICK自己。
1。C的谓语是WOULD PREFER TO，更喜欢的意思，是主观问题，“取非”后变成不喜欢，还是主观问题。而原文的推理是建立在利益基础上，是客观问题
2。取非是直言判断才能取非，假言判断没说到取非问题。
3。C的意思为：如果不考虑价格因素（请细考虑这句话的隐含含义），J和WE更愿意买美国货。而原文却说价格便宜才买，价格是个决定因素。这个考虑角度不一样，价格是个决定因素需要不考虑价格因素这样的假设吗。
(D) Demand for paper products made in Japan and Western Europe will not increase sharply during this year.
(E) Production of wood pulp by United States companies will not increase sharply during this year.