21. A low-pressure weather system is approaching Plainville; rainfall results from about 70 percent of such systems in the Plainville area. Moreover, the current season, spring, is the time of year in which thundershowers, which sometimes result from low-pressure systems, are most likely to occur in Plainville.
Knowing which one of the following, in addition to the information above, would be most useful for determining the probability that Plainville will have a thundershower soon?
(A) the percentage of thundershowers in Plainville that occur in the spring
(B) the percentage of spring rainfalls in Plainville that are thundershowers
(C) the percentage of thundershowers in Plainville that result from low-pressure systems
(D) whether low-pressure systems in other areas are associated with rainfall
(E) whether Plainville has more or fewer thundershowers each spring than do nearby towns
22. It is illogical to infer a second and different effect from a cause which is known only by one particular effect. This is incorrect because the inferred effect must necessarily be produced by some different characteristic of the cause than is the observed effect, which already serves entirely to describe the cause.
Which one of the following arguments makes the same logical error as the one described by the author in the passage?
(A) An anonymous donor gave a thousand dollars to our historical society. I would guess that that individual also volunteers at the children’s hospital.
(B) The radioactive material caused a genetic mutation, which, in turn, caused the birth defect. Therefore, the radioactive material caused the birth defect.
(C) The tiny, unseen atom is the source of immense power. It must be its highly complex structure that produces this power.
(D) The city orchestra received more funds from the local government this year than ever before. Clearly this administration is more civic-minded than previous ones.
(E) If I heat water, which is a liquid, it evaporates. If I heat hundreds of other liquids like water, they evaporate. Therefore, if I heat any liquid like water, it will evaporate.
Questions 23-24
Just as a bicycle chain may be too tight, so may one’s carefulness and conscientiousness be so tense as to hinder the running of one’s mind.
23. Which one of the following most closely parallels the reasoning used in the argument above?
(A) Just as a clock may be wound too tightly, so may one’s time be spent fruitlessly in the pursuit of perfection.
(B) Just as a carousel may spin too quickly, so may one’s rapid concentration on several problems prevent a resolution of difficulties.
(C) Just as a machine may be oiled too much, so may one’s heavy drinking of alcoholic beverages lead to complete dissipation.
(D) Just as a raging river may be frozen into stillness during the winter, so may one’s career falter at certain times of the year.
(E) Just as a boxer may become too tense before a big fight, so may one’s personal concerns stand in the way of professional success.
24. Which one of the following, if true, would most seriously weaken the argument?
(A) Bicycle chains are used to turn wheels, but the human mind is used to “turn” ideas.
(B) People and bicycles are similar only in that both may not function well under stress.
(C) Bicycles help people with transportation, but careful, conscientious thought helps to solve many different problems.
(D) Extreme tension helps a bicycle chain to function efficiently.
(E) People engage in poor reasoning whether they are careful and conscientious or not.
25. All of the best comedians have had unhappy childhoods. Yet, many people who have had happy childhoods are good comedians, and some good comedians who have had miserably unhappy childhoods are happy adults.
If the statements in the passage are true, which one of the following CANNOT be true?
(A) The proportion of good comedians who had unhappy childhoods is greater than the proportion of the best comedians who did.
(B) Some good comedians have had unhappy childhoods and are unhappy adults.
(C) Most of the best comedians are happy adults.
(D) More good comedians have had unhappy childhoods than have had happy childhoods.
(E) The proportion of comedians who are happy adults is higher than the proportion who are unhappy adults.
