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OG18-数学分册
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In the coordinate plane, line k passes through the origin and has slope 2. If points (3,y) and (x,4) are on line k, then x + y =
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OG18-数学分册
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Last year Department Store X had a sales total for December that was 4 times the average (arithmetic mean) of the monthly sales totals for January through November. The sales total for December was what fraction of the sales total for the year?
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OG18-数学分册
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$${(- 1.5)(1.2) - (4.5)(0.4)}\over{30} $$ =
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OG18-数学分册
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The average (arithmetic mean) length per film for a group of 21 films is t minutes. If a film that runs for 66 minutes is removed from the group and replaced by one that runs for 52 minutes, what is the average length per film, in minutes, for the new group of films, in terms of t ?
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OG18-数学分册
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If a basketball team scores an average (arithmetic mean) of x points per game for n games and then scores y points in its next game, what is the team's average score for the n + 1 games?
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OG18-数学分册
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What is the remainder when $$3^{24}$$is divided by 5 ?
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OG18-数学分册
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Which of the following lines in the xy-plane does not contain any point with integers as both coordinates?
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OG18
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Parland's alligator population has been declining in recent years, primarily because of hunting. Alligators prey heavily on a species of freshwater fish that is highly valued as food by Parlanders, who had hoped that the decline in the alligator population would lead to an increase in the numbers of these fish available for human consumption. Yet the population of this fish species has also declined, even though the annual number caught for human consumption has not increased.Which of the following, if true, most helps to explain the decline in the population of the fish species?
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OG18
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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.Which of the following would it be most useful to determine in order to evaluate the argument?
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PREP2012
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Southington University's fund-raisers succeeded in getting donations from 80 percent of the potential donors they contacted this year. This rate would be the expected rate if the only potential donors contacted were those who have donated in the past. But good fund-raisers constantly contact less likely prospects in an effort to expand the donor base. Thus the high success rate, far from showing that the fund-raisers did a good job, shows insufficient canvassing effort.
Which of the following, if true, most seriously weakens the argument?
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OG18-语文分册
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Historian: Newton developed mathematical concepts and techniques that are fundamental to modern calculus. Leibniz developed closely analogous concepts and techniques. It has traditionally been thought that these discoveries were independent. Researchers have, however, recently discovered notes of Leibniz` that discuss one of Newton`s books on mathematics. Several scholars have argued that since the book includes a presentation of Newton`s calculus concepts and techniques,and since the notes were written before Leibniz` own development of calculus concepts and techniques, it is virtually certain that the traditional view is false. A more cautious conclusion than this is called for, however. Leibniz` notes are limited to early sections of Newton`s book, sections that precede the ones in which Newton`s calculus concepts and techniques are presented. In the historian`s reasoning, the two portions in blodface play which of the following roles?
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OG18-数学分册
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A certain grocery purchased x pounds of produce for p dollars per pound. If y pounds of the produce had to be discarded due to spoilage and the grocery sold the rest for s dollars per pound, which of the following represents the gross profit on the sale of the produce?
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OG18-数学分册
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If x, y, and z are positive integers such that x is a factor of y, and x is a multiple of z, which of the following is NOT necessarily an integer?
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OG18-数学分册
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If n is a positive integer and $$n^{2} $$is divisible by 72, then the largest positive integer that must divide n is
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OG18-数学分册
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A square wooden plaque has a square brass inlay in the center, leaving a wooden strip of uniform width around the brass square. If the ratio of the brass area to the wooden area is 25 to 39, which of the following could be the width, in inches, of the wooden strip?I. 1II. 3III. 4
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OG18-数学分册
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A positive integer n is a perfect number provided that the sum of all the positive factors of n, including 1 and n, is equal to 2n. What is the sum of the reciprocals of all the positive factors of the perfect number 28 ?
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OG18-数学分册
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The closing price of Stock X changed on each trading day last month. The percent change in the closing price of Stock X from the first trading day last month to each of the other trading days last month was less than 50 percent. If the closing price on the second trading day last month was $10.00, which of the following CANNOT be the closing price on the last trading day last month?
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OG18-数学分册
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For every even positive intger m, f(m) represents the product of all even integers from 2 to m, inclusive. For example, f(12) = 2 x 4 x 6 x 8 x 10 x 12. What is the greatest prime factorof f(24)?
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OG18-数学分册
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 The figure shown above consists of three identical circles that are tangent to each other. If the area of the shaded region is $$64\sqrt{3} - 32π$$, what is the radius of each circle?
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OG18-数学分册
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If x is to be chosen at random from the set {1, 2, 3, 4} and y is to be chosen at random from the set {5, 6, 7}, what is the probability that xy will be even?
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