GRE-练习十一及答案解析.doc

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1、GRE-练习十一及答案解析(总分：46.00，做题时间：90 分钟)一、lilist-style-type:n(总题数：15，分数：15.00)1.Evan has 4 times as many books as David and 5 times as many as Jason. If Jason has more than 40 books, what is the least number of books that Evan could have? A. 200 B. 205 C. 210 D. 220 E. 240（分数：1.00）A.B.C.D.E.2.Judy plans t

2、o visit the National Gallery once each month in 2012 except in July and August when she plans to go three times each. A single admission costs $3.50, a pass valid for unlimited visits in any 3-month period can be purchased for $18, and an annual pass costs $60.00. What is the least amount, in dollar

3、s, that Judy can spend for her intended number of visits? （分数：1.00）填空项 1:_3.Alison is now three times as old as Jeremy, but 5 years ago, she was 5 times as old as he was. How old is Alison now? A. 10 B. 12 C. 24 D. 30 E. 36（分数：1.00）A.B.C.D.E.4.What is the largest prime factor of 255? A. 5 B. 15 C. 1

4、7 D. 51 E. 255（分数：1.00）A.B.C.D.E.5.If c is the product of a and b, which of the following is the quotient of a and b? （分数：1.00）A.B.C.D.E.6.If w widgets cost c cents, how many widgets can you get for d dollars? （分数：1.00）A.B.C.D.E.7.If 120% of a is equal to 80% of b, which of the following is equal to

5、 a + b? A. 1.5a B. 2a C. 2.5a D. 3a E. 5a（分数：1.00）A.B.C.D.E.8.In the figure below, WXYZ is a square whose sides are 12. AB, CD, EF, and GH are each 8, and are the diameters of the four semicircles. What is the area of the shaded region?（分数：1.00）A.B.C.D.E.9.If x and y are integers such that x3 = y2,

6、which of the following could not be the value of y?Indicate all such values. A. -1 B. 1 C. 8 D. 12 E. 16 F. 27（分数：1.00）A.B.C.D.E.F.10.What is a divided by a% of a? （分数：1.00）A.B.C.D.E.11.If an object is moving at a speed of 36 kilometers per hour, how many meters does it travel in one second? （分数：1.0

7、0）填空项 1:_12.On a certain French-American committee, of the members are men, and of the men are Americans. If of the committee members are French, what fraction of the members are American women? （分数：1.00）填空项 1:_13.For what value of x is 82x-4 = 16x? A. 2 B. 3 C. 4 D. 6 E. 8（分数：1.00）A.B.C.D.E.14.If 1

8、2a + 3b = 1 and 7b - 2a = 9, what is the average (arithmetic mean) of a and b ? A. 0.1 B. 0.5 C. 1 D. 2.5 E. 5（分数：1.00）A.B.C.D.E.15.If x% of y is 10, what is y? （分数：1.00）A.B.C.D.E.16. （分数：1.00）A.B.C.D.17. （分数：1.00）A.B.C.D.18. （分数：1.00）A.B.C.D.19. （分数：1.00）A.B.C.D.20. （分数：1.00）A.B.C.D.21. （分数：1.00）A.

9、B.C.D.22. （分数：1.00）A.B.C.D.23. （分数：1.00）A.B.C.D.24. （分数：1.00）A.B.C.D.25. （分数：1.00）A.B.C.D.26. （分数：1.00）A.B.C.D.27. （分数：1.00）A.B.C.D.28.The number of square inches in the surface area of a cube is equal to the number of cubic inches in its volume. （分数：1.00）A.B.C.D.29. （分数：1.00）A.B.C.D.30. （分数：1.00）A.

10、B.C.D.On the GRE there will typically be three questions based on any set of graphs. Accordingly, in each section of the model tests in this book, there are three data interpretation questions, each referring to the same set of graphs. However, to illustrate the variety of questions that can be aske

11、d, in this exercise set, for some of the graphs there are only two questions.Questions 1-2 refer to the following graphs.（分数：2.00）(1).What is the ratio of the amount of Vitamin C in 500 grams of orange to the amount of Vitamin C in 500 grams of orange juice? A. 4:7 B. 1:1 C. 7:4 D. 2:1 E. 4:1（分数：1.0

12、0）A.B.C.D.E.(2).How many grams of tomato would you have to eat to be certain of getting more vitamin C than you would get by eating 100 grams of raw broccoli? A. 300 B. 500 C. 750 D. 1200 E. 1650（分数：1.00）A.B.C.D.E.Questions 34 refer to the following graphs.（分数：2.00）(1).In 1996, what percent of fourt

13、h-graders did between 1 and 2 hours of homework per day? A. 5% B. 15% C. 25% D. 40% E. 55%（分数：1.00）A.B.C.D.E.(2).If in 1984 there were 2,000,000 eleventh- graders, and if between 1984 and 1996 the number of eleventh-graders increased by 10%, then approximately how many more eleventh-graders watched

14、1 hour or less of television in 1996 than in 1984? A. 25,000 B. 50,000 C. 75,000 D. 100,000 E. 150,000（分数：1.00）A.B.C.D.E.Questions 5-6 refer to the following graph.Total Sales of Coast Corporationin 2000:$1,000,000（分数：2.00）(1).If the above circle graph were drawn to scale, then which of the followin

15、g is closest to the difference in the degree measurements of the central angle of the sector representing Brand C and the central angle of the sector representing Brand D? A. 5 B. 12 C. 18 D. 25 E. 43（分数：1.00）A.B.C.D.E.(2).The total sales of Coast Corporation in 2005 were 50% higher than in 2000. If

16、 the dollar value of the sales of Brand A was 25% higher in 2005 than in 2000, then the sales of Brand A accounted for what percentage of total sales in 2005? A. 20% B. 25% C. （分数：1.00）A.B.C.D.E.Questions 7-8 refer to the following graphs.（分数：6.00）(1).To the nearest million, how many more students w

17、ere enrolled in school both public and private, preK-12 in 1970 than in 1988? A. 3,000,000 B. 6,000,000 C. 10,000,000 D. 44,000,000 E. 51,000,000（分数：1.00）A.B.C.D.E.(2).In 1988 there were 40,000,000 public school students in the United States, of whom 22% lived in the West. Approximately, how many pu

18、blic school students are projected to be living in the West in 2008? A. 9,000,000 B. 12,000,000 C. 15,000,000 D. 24,000,000 E. 66,000,000（分数：1.00）A.B.C.D.E.(3).Questions 9-10 refer to the following graph. To the nearest 5%, what percent of underweight adult females perceive themselves to be underwei

19、ght? （分数：1.00）填空项 1:_(4).The members of which of the four groups had the least accurate perception of their body weight? A. Underweight B. Normal weight C. Moderately overweight D. Severely overweight E. It cannot be determined from the information given in the graph.（分数：1.00）A.B.C.D.E.(5).Questions

20、 11-12 refer to the following table. In 1979, residents of New York City paid both New York State and New York City tax. Residents of New York State who lived and worked outside of New York City paid only New York State tax. In 1979 how much tax, in dollars, would a resident of New York State who li

21、ved and worked outside New York City have paid on a taxable income of $16,100? （分数：1.00）_(6).In 1979, how much more total tax would a resident of New York City who had a taxable income of $36,500 pay, compared to a resident of New York City who had a taxable income of $36,000? A. $21.50 B. $43 C. $7

22、0 D. $91.50 E. $183（分数：1.00）A.B.C.D.E.Questions 13-14 refer to the following tables.（分数：2.00）(1).For how many of the countries listed in the graphs is it true that the life expectancy of a female born in 1955 was higher than the life expectancy of a male born in 1990? A. None B. 1 C. 2 D. 3 E. 4（分数：

23、1.00）A.B.C.D.E.(2).By sex and nationality, who had the greatest increase in life expectancy between 1955 and 1990? A. A South Korean female B. A South Korean male C. A Costa Rican female D. A Costa Rican male E. A Norwegian female（分数：1.00）A.B.C.D.E.Questions 15-16 refer to the following graph.（分数：2.

24、00）(1).If in 1998 there were 10,000 bias-motivated offenses based on ethnicity, how many more offenses were based on religion than on sexual orientation? A. 4 B. 40 C. 400 D. 4000 E. 40,000（分数：1.00）A.B.C.D.E.(2).If after further analysis it was determined that between 25% and 50% of the offenses inc

25、luded under Religion were, in fact, not bias-motivated, and those offenses were removed from the study, which of the following could be the percentage of bias-motivated offenses based on race?Indicate all such percentages. A. 59% B. 60% C. 61% D. 62% E. 63% F. 64% G. 65%（分数：1.00）A.B.C.D.E.F.G.GRE-练习

26、十一答案解析(总分：46.00，做题时间：90 分钟)一、lilist-style-type:n(总题数：15，分数：15.00)1.Evan has 4 times as many books as David and 5 times as many as Jason. If Jason has more than 40 books, what is the least number of books that Evan could have? A. 200 B. 205 C. 210 D. 220 E. 240（分数：1.00）A.B.C.D. E.解析：Test the answer c

27、hoices starting with the smallest value. If Evan had 200 books, Jason would have 40. But Jason has more than 40, so 200 is too small. Trying 205 and 210, we see that neither is a multiple of 4, so David wouldnt have a whole number of books. Finally, 220 works. (So does 240, but we shouldnt even test

28、 it since we want the least value.) *Since Jason has at least 41 books, Evan has at least 41 x 5 = 205. But Evans total must be a multiple of 4 and 5, hence of 20. The smallest multiple of 20 greater than 205 is 220.2.Judy plans to visit the National Gallery once each month in 2012 except in July an

29、d August when she plans to go three times each. A single admission costs $3.50, a pass valid for unlimited visits in any 3-month period can be purchased for $18, and an annual pass costs $60.00. What is the least amount, in dollars, that Judy can spend for her intended number of visits? （分数：1.00）填空项

30、 1:_ （正确答案：49.50）解析：Judy intends to go to the Gallery 16 times during the year. Buying a single admission each time would cost 16 $3.50 = $56, which is less than the annual pass. If she bought a 3-month pass for June, July, and August, she would pay $18 plus $31.50 for 9 single admissions (9 $3.50),

31、 for a total expense of $49.50, which is the least expensive option.3.Alison is now three times as old as Jeremy, but 5 years ago, she was 5 times as old as he was. How old is Alison now? A. 10 B. 12 C. 24 D. 30 E. 36（分数：1.00）A.B.C.D. E.解析：Use TACTIC 1: backsolve starting with C. If Alison is now 24

32、, Jeremy is 8, and 5 years ago, they would have been 19 and 3, which is more than 5 times as much. Eliminate A, B, and C, and try a bigger value. If Alison is now 30, Jeremy is 10, and 5 years ago, they would have been 25 and 5. Thats it; 25 is 5 times 5. *If Jeremy is now x, Alison is 3x, and 5 yea

33、rs ago they were x- 5 and 3x- 5, respectively. Now, solve: 3x- 5 = 5(x- 5) * 3x- 5 = 5x- 25* 2x=20*x= 10*3x=30.4.What is the largest prime factor of 255? A. 5 B. 15 C. 17 D. 51 E. 255（分数：1.00）A.B.C. D.E.解析：Test the choices starting with C: 255 is divisible by 17 (255 = 17 15), so this is a possible

34、answer. Does 255 have a larger prime factor? Neither Choice D nor E is prime, so the answer must be Choice C.5.If c is the product of a and b, which of the following is the quotient of a and b? （分数：1.00）A.B. C.D.E.解析：Use TACTIC 2. Pick simple values for a, b, and c. Let a = 3, b = 2, and c = 6. Then

35、 a - b = 3/2. Without these values of a, b, and c, only B is equal to 3/2. *6.If w widgets cost c cents, how many widgets can you get for d dollars? （分数：1.00）A. B.C.D.E.解析：Use TACTIC 2. If 2 widgets cost 10 cents, then widgets cost 5 cents each, and for 3 dollars, you can get 60. Which of the choice

36、s equals 60 when w = 2, c= 10, and d = 3? Only A. *7.If 120% of a is equal to 80% of b, which of the following is equal to a + b? A. 1.5a B. 2a C. 2.5a D. 3a E. 5a（分数：1.00）A.B.C. D.E.解析：Since 120% of 80 = 80% of 120, let a = 80 and b = 120. Then a + b = 200, and 200 + 80 = 2.5.8.In the figure below,

37、 WXYZ is a square whose sides are 12. AB, CD, EF, and GH are each 8, and are the diameters of the four semicircles. What is the area of the shaded region?（分数：1.00）A.B.C. D.E.解析：If you dont know how to solve this, you must use TACTIC 4 and guess after eliminating the absurd choices. Which choices are

38、 absurd? Certainly, A and B, both of which are negative. Also, since Choice D is about 94, which is much more than half the area of the square, it is much too big. Guess between Choice C (about 43) and Choice E (about 50). If you remember that the way to find shaded areas is to subtract, guess C.*Th

39、e area of the square is 122 = 144. The area of each semicircle is 8, one-half the area of a circle of radius 4. So together the areas of the semicircles is 32.9.If x and y are integers such that x3 = y2, which of the following could not be the value of y?Indicate all such values. A. -1 B. 1 C. 8 D.

40、12 E. 16 F. 27（分数：1.00）A.B.C.D. E. F.解析：Test each choice until you find all the correct answers.(A) Could y = -1? Is there an integer x such that x3 = (-1)2 = 1? Yes, x = 1.(B) Similarly, if y = 1, x = 1.(C) Could y = 8? Is there an integer x such that x3 = (8)2 = 64? Yes, x = 4.(D) Could y = 12? Is

41、 there an integer such that x3 = 122 = 144? No, 53 = 125, which is too small, and 63 = 216, which is too big.(E) Could y = 16? Is there an integer x such that x3 = 162 = 256? No, 63 = 216, which is too small; and 73 = 343, which is too big.(F) Could y = 27? Is there an integer x such that x3 = 272 =

42、 729? Yes, 93 = 729. The answer is D and E.10.What is a divided by a% of a? （分数：1.00）A.B. C.D.E.解析：* *Use TACTICS 2 and 3: replace a by a number, and use 100 since the problem involves percents. 100 + (100% of 100) = 100 + 100 = 1. Test each choice; which ones equal 1 when a = 100. Both A and B: *.

43、Eliminate Choices C, D, and E, and test A and B with another value for a. 50 + (50% of 50) = 50 + (25) = 2. Now, only B works*11.If an object is moving at a speed of 36 kilometers per hour, how many meters does it travel in one second? （分数：1.00）填空项 1:_ （正确答案：10）解析：Set up a ratio: * *Use TACTIC 1: Te

44、st choices starting with C: 100 meters/second = 6000 meters/minute = 360,000 meters/hour = 360 kilometers/hour. Not only is that too big, it is too big by a factor of 10. The answer is 10.12.On a certain French-American committee, of the members are men, and of the men are Americans. If of the commi

45、ttee members are French, what fraction of the members are American women? （分数：1.00）填空项 1:_ （正确答案：*）解析：Use TACTIC 3. The LCM of all the denominators is 120, so assume that the committee has 120 members. Then there are* men and 40 women. Of the 80 men 30* are American. Since there are 72* French membe

46、rs, there are 120 - 72 = 48 Americans, of whom 30 are men, so the other 18 are women. Finally, the fraction of American women is* This is illustrated in the Venn diagram below. *13.For what value of x is 82x-4 = 16x? A. 2 B. 3 C. 4 D. 6 E. 8（分数：1.00）A.B.C.D. E.解析：Use the laws of exponents to simplif

47、y the equation, and then solve it:82x-4 = 16x*(23)2x-4 = (24)x* 3(2x-4) = 4x* 6x- 12 = 4x*2x= 12*x= 6.14.If 12a + 3b = 1 and 7b - 2a = 9, what is the average (arithmetic mean) of a and b ? A. 0.1 B. 0.5 C. 1 D. 2.5 E. 5（分数：1.00）A.B. C.D.E.解析：Add the two equations: * Do not waste time solving for a a

48、nd b.15.If x% of y is 10, what is y? （分数：1.00）A.B.C. D.E.解析：Pick easy-to-use numbers. Since 100% of 10 is 10, let x= 100 and y = 10. When x = 100, Choices C and E are each 10. Eliminate Choices A, B, and D, and try some other numbers: 50% of 20 is 10. Of Choices C and E, only C = 20 when x = 50.16. （分数：1.00）A.B. C.D.解析：Using