1.A milepost on the towpath read “21” on the side facing the hiker as she approached it and “23” on its back. She reasoned that the next milepost forward on the path would indicate that she was halfway between one end of the path and the other. However, the milepost one mile further on read “20” facing her and “24” behind.Which of the following, if true, would explain the discrepancy described above?
(A) The numbers on the next milepost had been reversed.
(B) The numbers on the mileposts indicate kilometers, not miles.
(C) The facing numbers indicate miles to the end of the path, not miles from the beginning.
(D) A milepost was missing between the two the hiker encountered.
(E) The mileposts had originally been put in place for the use of mountain bikers, not for hikers.
2. Airline: Newly developed collision-avoidance systems, although not fully tested to discover potential malfunctions, must be installed immediately in passenger planes. Their mechanical warnings enable pilots to avoid crashes.Pilots: Pilots will not fly in planes with collision-avoidance systems that are not fully tested. Malfunctioning systems could mislead pilots, causing crashes.The pilots’ objection is most strengthened if which of the following is true?
(A) It is always possible for mechanical devices to malfunction.
(B) Jet engines, although not fully tested when first put into use, have achieved exemplary performance and safety records.
(C) Although collision-avoidance systems will enable pilots to avoid some crashes, the likely malfunctions of the not-fully-tested systems will cause even more crashes.
(D) Many airline collisions are caused in part by the exhaustion of overworked pilots.
(E) Collision-avoidance systems, at this stage of development, appear to have worked better in passenger planes than in cargo planes during experimental flights made over a six-month period.
3. Guitar strings often go “dead”—become less responsive and bright in tone—after a few weeks of intense use. A researcher whose son is a classical guitarist hypothesized that dirt and oil, rather than changes in the material properties of the string, were responsible.Which of the following investigations is most likely to yield significant information that would help to evaluate the researcher’s hypothesis?
(A) Determining if a metal alloy is used to make the strings used by classical guitarists
(B) Determining whether classical guitarists make their strings go dead faster than do folk guitarists
(C) Determining whether identical lengths of string, of the same gauge, go dead at different rates when strung on various brands of guitars
(D) Determining whether a dead string and a new string produce different qualities of sound
(E) Determining whether smearing various substances on new guitar strings causes them to go dead
4. Most consumers do not get much use out of the sports equipment they purchase. For example, seventeen percent of the adults in the United States own jogging shoes, but only forty-five percent of the owners jog more than once a year, and only seventeen percent jog more than once a week.Which of the following, if true, casts most doubt on the claim that most consumers get little use out of the sports equipment they purchase?
(A) Joggers are most susceptible to sports injuries during the first six months in which they jog.
(B) Joggers often exaggerate the frequency with which they jog in surveys designed to elicit such information.
(C) Many consumers purchase jogging shoes for use in activities other than jogging.
(D) Consumers who take up jogging often purchase an athletic shoe that can be used in other sports.
(E) Joggers who jog more than once a week are often active participants in other sports as well.
5. Two decades after the Emerald River Dam was built, none of the eight fish species native to the Emerald River was still reproducing adequately in the river below the dam. Since the dam reduced the annual range of water temperature in the river below the dam from 50 degrees to 6 degrees, scientists have hypothesized that sharply rising water temperatures must be involved in signaling the native species to begin the reproductive cycle.Which of the following statements, if true, would most strengthen the scientists’ hypothesis?
(A) The native fish species were still able to reproduce only in side streams of the river below the dam where the annual temperature range remains approximately 50 degrees.
(B) Before the dam was built, the Emerald River annually overflowed its banks, creating backwaters that were critical breeding areas for the native species of fish.
(C) The lowest recorded temperature of the Emerald River before the dam was built was 34 degrees, whereas the lowest recorded temperature of the river after the dam was built has been 43 degrees.
(D) Nonnative species of fish, introduced into the Emerald River after the dam was built, have begun competing with the declining native fish species for food and space.
(E) Five of the fish species native to the Emerald River are not native to any other river in North America.
6. It is true that it is against international law to sell plutonium to countries that do not yet have nuclear weapons. But if United States companies do not do so, companies in other countries will.Which of the following is most like the argument above in its logical structure?
(A) It is true that it is against the police department’s policy to negotiate with kidnappers. But if the police want to prevent loss of life, they must negotiate in some cases.
(B) It is true that it is illegal to refuse to register for military service. But there is a long tradition in the United States of conscientious objection to serving in the armed forces.
(C) It is true that it is illegal for a government official to participate in a transaction in which there is an apparent conflict of interest. But if the facts are examined carefully, it will clearly be seen that there was no actual conflict of interest in the defendant’s case.
(D) It is true that it is against the law to burglarize people’s homes. But someone else certainly would have burglarized that house if the defendant had not done so first.
(E) It is true that company policy forbids supervisors to fire employees without two written warnings. But there have been many supervisors who have disobeyed this policy.
7. In recent years many cabinetmakers have been winning acclaim as artists. But since furniture must be useful, cabinetmakers must exercise their craft with an eye to the practical utility of their product. For this reason, cabinetmaking is not art.Which of the following is an assumption that supports drawing the conclusion above from the reason given for that conclusion?
(A) Some furniture is made to be placed in museums, where it will not be used by anyone.
(B) Some cabinetmakers are more concerned than others with the practical utility of the products they produce.
(C) Cabinetmakers should be more concerned with the practical utility of their products than they currently are.
(D) An object is not an art object if its maker pays attention to the object’s practical utility.
(E) Artists are not concerned with the monetary value of their products.
8. Although custom prosthetic bone replacements produced through a new computer-aided design process will cost more than twice as much as ordinary replacements, custom replacements should still be cost-effective. Not only will surgery and recovery time be reduced, but custom replacements should last longer, thereby reducing the need for further hospital stays.Which of the following must be studied in order to evaluate the argument presented above?
(A) The amount of time a patient spends in surgery versus the amount of time spent recovering from surgery
(B) The amount by which the cost of producing custom replacements has declined with the introduction of the new technique for producing them
(C) The degree to which the use of custom replacements is likely to reduce the need for repeat surgery when compared with the use of ordinary replacements
(D) The degree to which custom replacements produced with the new technique are more carefully manufactured than are ordinary replacements
(E) The amount by which custom replacements produced with the new technique will drop in cost as the production procedures become standardized and applicable on a larger scale
9. Extinction is a process that can depend on a variety of ecological, geographical, and physiological variables. These variables affect different species of organisms in different ways, and should, therefore, yield a random pattern of extinctions. However, the fossil record shows that extinction occurs in a surprisingly definite pattern, with many species vanishing at the same time.Which of the following, if true, forms the best basis for at least a partial explanation of the patterned extinctions revealed by the fossil record?
(A) Major episodes of extinction can result from widespread environmental disturbances that affect numerous different species.
(B) Certain extinction episodes selectively affect organisms with particular sets of characteristics unique to their species.
(C) Some species become extinct because of accumulated gradual changes in their local environments.
(D) In geologically recent times, for which there is no fossil record, human intervention has changed the pattern of extinctions.
(E) Species that are widely dispersed are the least likely to become extinct.
10. Neither a rising standard of living nor balanced trade, by itself, establishes a country’s ability to compete in the international marketplace. Both are required simultaneously since standards of living can rise because of growing trade deficits and trade can be balanced by means of a decline in a country’s standard of living.If the facts stated in the passage above are true, a proper test of a country’s ability to be competitive is its ability to
(A) balance its trade while its standard of living rises
(B) balance its trade while its standard of living falls
(C) increase trade deficits while its standard of living rises
(D) decrease trade deficits while its standard of living falls
(E) keep its standard of living constant while trade deficits rise
