GMAT
In the years following an eight-cent increase in the federal tax on a pack of cigarettes, sales of cigarettes fell ten percent. In contrast, in the year prior to the tax increase, sales had fallen one percent. The volume of cigarette sales is therefore strongly related to the after-tax price of a pack of cigarettes.The argument above requires which of the following assumptions?
A sudden increase in the production of elephant ivory artifacts on the Mediterranean coast of North Africa occurred in the tenth century. Historians explain this increase as the result of an area opening up as a new source of ivory and argue on this basis that the important medieval trade between North Africa and East Africa began at this period.Each of the following, if true, provides some support for the historians' account described above EXCEPT:
In response to viral infection, the immune systems of mice typically produce antibodies that destroy the virus by binding to proteins on its surface. Mice infected with a herpesvirus generally develop keratitis, a degenerative disease affecting part of the eye. Since proteins on the surface of cells in this part of the eye closely resemble those on the herpesvirus surface, scientists hypothesize that these cases of keratitis are caused by antibodies to herpesvirus.Which of the following, if true, gives the greatest additional support to the scientists' hypothesis?
The growing popularity of computer-based activities was widely expected to result in a decline in television viewing, since it had been assumed that people lack sufficient free time to maintain current television-viewing levels while spending increasing amounts of free time on the computer. That assumption, however, is evidently false: in a recent mail survey concerning media use, a very large majority of respondents who report increasing time spent per week using computers report no change in time spent watching television.In order to evaluate the argument, it would be most useful to determine which of the following?
In 1992 outlaw fishing boats began illegally harvesting lobsters from the territorial waters of the country of Belukia. Soon after, the annual tonnage of lobster legally harvested in Belukian waters began declining; in 1996, despite there being no reduction in the level of legal lobster fishing activity, the local catch was 9,000 tons below pre-1992 levels. It is therefore highly likely that the outlaw fishing boats harvested about 9,000 tons of lobster illegally that year.Which of the following is an assumption on which the argument depends?
Scientists typically do their most creative work before the age of forty. It is commonly thought that this happens because aging by itself brings about a loss of creative capacity. However, a study has found that almost all scientists who produce highly creative work beyond the age of forty entered their fields late and less than a dozen years before their creative breakthroughs. Since creative breakthroughs by scientists under forty also generally occur within a dozen years of the scientist's entry into the field, the study's finding strongly suggests that the real reason why scientists over forty rarely produce highly creative work is not due to age but rather because most have spent too long in their fields.In the argument given, the two portions in boldface play which of the following roles?
Lyme disease is caused by a bacterium transmitted to humans by deer ticks. Generally deer ticks pick up the bacterium while in the larval stage from feeding on infected white-footed mice. However, certain other species on which the larvae feed do not harbor the bacterium. Therefore, if the population of these other species were increased, the number of ticks acquiring the bacterium and hence the number of people contracting Lyme disease-would likely decline.Which of the following, if true, most strengthens the argument?
The percentage of households with an annual income of more than $40,000 is higher in Merton county than in any other county. However, the percentage of households with an annual income of $60,000 or more is highest in Sommer county.If the statements above are true, which of the following can properly be concluded on the basis of them?
Ecologist: The Scottish Highlands were once the site of extensive forests, but these forests have mostly disappeared and been replaced by peat bogs. The common view is that the Highlands' deforestation was caused by human activity, especially agriculture. However, agriculture began in the Highlands less than 2,000 years ago. Peat bogs, which consist of compressed decayed vegetable matter, build up by only about one foot per 1,000 years and, throughout the Highlands, remains of trees in peat bogs are almost all at depths great than four feet. Since climate changes that occurred between 7,000 and 4,000 years ago favored the development of peat bogs rather than the survival of forests, the deforestation was more likely the result of natural processes than of human activity.In the ecologist's argument the two portions in boldface play which of the following roles?
Which of the following, if true, most logically completes the passage?A recent poll found that over 80 percent of the residents of Nalmed Province favored a massive expansion of the commuter rail system as a means of significantly easing congestion on the province's highways and were willing to help pay for the expansion through an increase in their taxes. Nevertheless, the poll results indicate that expansion of the rail system, if successfully completed, would be unlikely to achieve its goal of easing congestion, because _______.
For most people, the left half of the brain controls linguistic capabilities, but some people have their language centers in the right half. When a language center of the brain is damaged, for example by a stroke, linguistic capabilities are impaired in some way. Therefore, people who have suffered a serious stroke on the left side of the brain without suffering any such impairment must have their language centers in the right half.Which of the following is an assumption on which the reasoning in the argument above depends?
Press Secretary: Our critics claim that the President's recent highway project cancellations demonstrate a vindictive desire to punish legislative districts controlled by opposition parties. They offer as evidence the fact that 90 percent of the projects canceled were in such districts. But all of the canceled projects had been identified as wasteful in a report written by respected nonpartisan auditors. So the President's choice was clearly motivated by sound budgetary policy, not partisan politics.Which of the following is an assumption on which the press secretary's argument depends?
Some species of Arctic birds are threatened by recent sharp increases in the population of snow geese, which breed in the Arctic and are displacing birds of less vigorous species. Although snow geese are a popular quarry for hunters in the southern regions where they winter, the hunting season ends if and when hunting has reduced the population by five percent, according to official estimates. Clearly, dropping this restriction would allow the other species to recover.Which of the following, if true, most seriously undermines the argument?
Eurasian watermilfoil, a weed not native to Frida Lake, has reproduced prolifically since being accidentally introduced there. In order to eliminate the weed, biologists proposed treating infested parts of the lake with a certain herbicide that is nontoxic for humans and aquatic animals. However, the herbicide might damage populations of certain rare plant species that the lake contains. For this reason local officials rejected the proposal.Which of the following, if true, points out the most serious weakness in the officials' grounds for rejecting the biologists' proposal?
Fact: Asthma, a bronchial condition, is much less common ailment than hay fever, an allergic inflammation of the nasal passages.Fact: Over 95 percent of people who have asthma also suffer from hay fever.If the information given as facts above is true, which of the following must also be true?
Aroca City currently funds its public schools through taxes on property. In place of this system, the city plans to introduce a sales tax of three percent on all retail sales in the city. Critics protest that three percent of current retail sales falls short of the amount raised for schools by property taxes. The critics are correct on this point. Nevertheless, implementing the plan will probably not reduce the money going to Aroca's schools. Several large retailers have selected Aroca City as the site for huge new stores, and these are certain to draw large numbers of shoppers from neighboring municipalities, where sales are taxed at rates of six percent and more. In consequence, retail sales in Aroca City are bound to increase substantially.In the argument given, the two potions in boldface play which of the following roles?
In each of the past five years, Barraland's prison population has increased. Yet, according to official government statistics, for none of those years has there been either an increase in the number of criminal cases brought to trial, or an increase in the rate at which convictions have been obtained. Clearly, therefore, the percentage of people convicted of crimes who are being given prison sentences is on the increase.Which of the following, if true, most seriously weakens the argument?
Because visual inspection cannot reliably distinguish certain skin discolorations from skin cancers, dermatologists at clinics have needed to perform tests of skin tissue taken from patients. At Westville Hospital, dermatological diagnostic costs were reduced by the purchase of a new imaging machine that diagnoses skin cancer in such cases as reliably as the tissue tests do. Consequently, even though the machine is expensive, a dermatological clinic in Westville is considering buying one to reduce diagnostic costs.Which of the following would it be most useful for the clinic to establish in order to make its decision?
Environmental organizations want to preserve the land surrounding the Wilgrinn Wilderness Area from residential development. They plan to do this by purchasing that land from the farmers who own it. That plan is ill-conceived: if the farmers did sell their land, they would sell it to the highest bidder, and developers would outbid any other bidders. On the other hand, these farmers will never actually sell any of the land, provided that farming it remains viable. But farming will not remain viable if the farms are left unmodernized, and most of the farmers lack the financial resources modernization requires. And that is exactly why a more sensible preservation strategy would be to assist the farmers to modernize their farms to the extent needed to maintain viability.In the argument as a whole, the two boldface proportions play which of the following roles?