GRE-90及答案解析.doc

1、GRE-90及答案解析(总分：25.00，做题时间：90 分钟)一、SECTION 1(总题数：24，分数：25.00)Average U.S. apple prices by consumption2001 2002 2003 2004All sales (cents per pound) 15.80 18.90 20.90 15.80Fresh consumption (cents per pound) 22.90 25.80 29.40 21.70All processing (dollars per ton) 108.00130.00131.00107.00Canned (dollar

2、s per ton) 139.00161.00154.00149.00Juice and cider (dollars per ton) 83.40 104.00103.0073.00Frozen (dollars per ton) 139.00175.00173.00172.00Dried (dollars per ton) 84.70 108.00107.0077.30Data from U.S. Apple Association www. usapple, org.（分数：2.00）(1).Comparing 2001 to 2003 what is the approximate p

3、ercentage change in value of the apple crop?A. increase of 25%B. decrease of 25%C. increase of 6%D. decrease of 6%E. increase of 12%（分数：1.00）A.B.C.D.E.(2).Which is worth the most?A. 25% of the 2001 crop sold for juiceB. 10% of the 2002 crop sold for canningC. 5% of the 2003 crop sold for freezingD.

4、15% of the 2004 crop sold driedE. 1% of the 2001 crop sold fresh（分数：1.00）A.B.C.D.E.1.George earned 80, 85 and 90 on the first three tests in his geography class. Because he didnt have time to study, he decides to guess randomly on the final test. That test has ten true-false questions, each worth 10

5、 points. What is the probability his final average is more than 85?（分数：1.00）A.B.C.D.E.2.Jordan has taken 5 math tests so far this semester. If he gets a 70 on his next test, it will lower the average (arithmetic mean) of his test scores by 4 points. What is his average now?（分数：1.00）填空项 1:_3.Two buse

6、s are 515 miles apart. At 9:30 a. m., they start traveling toward each other at rates of 48 and 55 miles per hour. At what time will they pass each other?A. 1:30 p.m. B. 2:00 p.m.C. 2:30 p.m. D. 3:00 p.m.E. 3:30 p. m.（分数：1.00）A.B.C.D.E.4. （分数：1.00）A.B.C.D.5.In a certain store, each record costs X do

7、llars and each tape costs Y dollars. The total cost of 3 records and 2 tapes is $39.（分数：1.00）A.B.C.D.6.In a singles tennis tournament that has 125 entrants, a player is eliminated whenever he loses a match. How many matches are played in the entire tournament?（分数：1.00）填空项 1:_7.D. 16 E. 18（分数：1.00）8.

8、Every year between 70% and 85% of the students at Central High School attend the homecoming rally. If one year 1435 students attended the rally, which of the following could have been the number of students at Central High School that year? Indicate all possible numbers of students.A. 1675 B. 1775 C

9、 1875D. 1975 E. 2075（分数：1.00）9.Martina needs 35 gallons of fuel in each winter month to heat her home. Each spring and fall month she uses 15 gallons of fuel. She uses no fuel during the summer. What part of her annual heating bill is spent during the winter?Give your answer as a fraction :（分数：1.00

10、填空项 1:_10. （分数：1.00）A.B.C.D.11.A jar contains ,t red and n green marbles where n2. You pick two marbles from the jar.（分数：1.00）A.B.C.D.12.If a and b are the lengths of the legs of a right triangle whose hypotenuse is 10 and whose area is 20,what is the value of (a +b.2?A. 100 B. 120 C. 140D.180 E.20

11、0（分数：1.00）A.B.C.D.E.13.In a normal distribution, 68% of the scores lie within one standard deviation of the mean. If the SAT scores of all the high school juniors in Center City followed a normal distribution with a mean of 500 and a standard deviation of 100, and if 10,200 students scored between 4

12、00 and 500, approximately how many students scored above 600?A. 2,400 B. 4,800 C. 5.100D. 7,200 E. 9,600（分数：1.00）A.B.C.D.E.14.D. 2.0 E. 2.5 F. 3.0（分数：1.00）15.A school group charters three identical buses and occupies of the seats. After of the passengers leave, the remaining passengers use only two

13、of the buses.（分数：1.00）A.B.C.D.16. （分数：1.00）A.B.C.D.17.The operation is defined for all positive numbers r and t by r t=（分数：1.00）A.B.C.D.18.Marias average after three tests was 86. She scored 94 on her fourth test and has only one test remaining.（分数：1.00）A.B.C.D.19.An investor wants to sell some of t

14、he stock that he owns in Micro Tron and Dynaco Corporations. He can sell Micro Tron stock for $ 36 per share, and he can sell Dynaco stock for $ 52 per share. If he sells 300 shares altogether at an average price per share of $40, how many shares of Dynaco stock has he sold?A. 52 B. 75 C. 92D. 136 E

15、 184（分数：1.00）A.B.C.D.E.20.Because her test turned out to be more difficult than she intended it to be, a teacher decided to adjust the grades by deducting only half the number of points a student missed. For example, if a student missed 10 points, she received a 95 instead of a 90. Before the grade

16、s were adjusted the class average was A. What was the average after the adjustment?（分数：1.00）A.B.C.D.E.21.A case of soda costs $ 16.75. The cost of p individual cans of soda is $1.20 per can.（分数：1.00）A.B.C.D.22.A developer has land that has x feet of lake frontage. The land is to be subdivided into l

17、ots, each of which is to have either 80 feet or 100 feet of lake frontage. If （分数：1.00）A.B.C.D.E.23.Each integer from 1 to 50 whose units digit is a 3 is written on a slip of paper and placed in a box. If two slips of paper are drawn at random, what is the probability that both the numbers picked ar

18、e prime?（分数：1.00）填空项 1:_GRE-90答案解析(总分：25.00，做题时间：90 分钟)一、SECTION 1(总题数：24，分数：25.00)Average U.S. apple prices by consumption2001 2002 2003 2004All sales (cents per pound) 15.80 18.90 20.90 15.80Fresh consumption (cents per pound) 22.90 25.80 29.40 21.70All processing (dollars per ton) 108.00130.00131

19、00107.00Canned (dollars per ton) 139.00161.00154.00149.00Juice and cider (dollars per ton) 83.40 104.00103.0073.00Frozen (dollars per ton) 139.00175.00173.00172.00Dried (dollars per ton) 84.70 108.00107.0077.30Data from U.S. Apple Association www. usapple, org.（分数：2.00）(1).Comparing 2001 to 2003 wh

20、at is the approximate percentage change in value of the apple crop?A. increase of 25%B. decrease of 25%C. increase of 6%D. decrease of 6%E. increase of 12%（分数：1.00）A. B.C.D.E.解析：(2).Which is worth the most?A. 25% of the 2001 crop sold for juiceB. 10% of the 2002 crop sold for canningC. 5% of the 200

21、3 crop sold for freezingD. 15% of the 2004 crop sold driedE. 1% of the 2001 crop sold fresh（分数：1.00）A. B.C.D.E.解析：1.George earned 80, 85 and 90 on the first three tests in his geography class. Because he didnt have time to study, he decides to guess randomly on the final test. That test has ten true

22、false questions, each worth 10 points. What is the probability his final average is more than 85?（分数：1.00）A.B.C.D. E.解析：2.Jordan has taken 5 math tests so far this semester. If he gets a 70 on his next test, it will lower the average (arithmetic mean) of his test scores by 4 points. What is his ave

23、rage now?（分数：1.00）填空项 1:_ （正确答案：94）解析：3.Two buses are 515 miles apart. At 9:30 a. m., they start traveling toward each other at rates of 48 and 55 miles per hour. At what time will they pass each other?A. 1:30 p.m. B. 2:00 p.m.C. 2:30 p.m. D. 3:00 p.m.E. 3:30 p. m.（分数：1.00）A.B.C. D.E.解析：4. （分数：1.00）

24、A.B. C.D.解析：5.In a certain store, each record costs X dollars and each tape costs Y dollars. The total cost of 3 records and 2 tapes is $39.（分数：1.00）A.B.C.D. 解析：6.In a singles tennis tournament that has 125 entrants, a player is eliminated whenever he loses a match. How many matches are played in th

25、e entire tournament?（分数：1.00）填空项 1:_ （正确答案：124）解析：7.D. 16 E. 18（分数：1.00）解析：8.Every year between 70% and 85% of the students at Central High School attend the homecoming rally. If one year 1435 students attended the rally, which of the following could have been the number of students at Central High

26、School that year? Indicate all possible numbers of students.A. 1675 B. 1775 C. 1875D. 1975 E. 2075（分数：1.00）解析：9.Martina needs 35 gallons of fuel in each winter month to heat her home. Each spring and fall month she uses 15 gallons of fuel. She uses no fuel during the summer. What part of her annual

27、heating bill is spent during the winter?Give your answer as a fraction :（分数：1.00）填空项 1:_ （正确答案： ）解析：10. （分数：1.00）A.B. C.D.解析：11.A jar contains ,t red and n green marbles where n2. You pick two marbles from the jar.（分数：1.00）A.B.C. D.解析：12.If a and b are the lengths of the legs of a right triangle who

28、se hypotenuse is 10 and whose area is 20,what is the value of (a +b.2?A. 100 B. 120 C. 140D.180 E.200（分数：1.00）A.B.C.D. E.解析：13.In a normal distribution, 68% of the scores lie within one standard deviation of the mean. If the SAT scores of all the high school juniors in Center City followed a normal

29、distribution with a mean of 500 and a standard deviation of 100, and if 10,200 students scored between 400 and 500, approximately how many students scored above 600?A. 2,400 B. 4,800 C. 5.100D. 7,200 E. 9,600（分数：1.00）A.B. C.D.E.解析：14.D. 2.0 E. 2.5 F. 3.0（分数：1.00）解析：15.A school group charters three i

30、dentical buses and occupies of the seats. After of the passengers leave, the remaining passengers use only two of the buses.（分数：1.00）A.B.C. D.解析：16. （分数：1.00）A.B. C.D.解析：17.The operation is defined for all positive numbers r and t by r t=（分数：1.00）A. B.C.D.解析：18.Marias average after three tests was 8

31、6. She scored 94 on her fourth test and has only one test remaining.（分数：1.00）A. B.C.D.解析：19.An investor wants to sell some of the stock that he owns in Micro Tron and Dynaco Corporations. He can sell Micro Tron stock for $ 36 per share, and he can sell Dynaco stock for $ 52 per share. If he sells 30

32、0 shares altogether at an average price per share of $40, how many shares of Dynaco stock has he sold?A. 52 B. 75 C. 92D. 136 E. 184（分数：1.00）A.B. C.D.E.解析：20.Because her test turned out to be more difficult than she intended it to be, a teacher decided to adjust the grades by deducting only half the

33、 number of points a student missed. For example, if a student missed 10 points, she received a 95 instead of a 90. Before the grades were adjusted the class average was A. What was the average after the adjustment?（分数：1.00）A. B.C.D.E.解析：21.A case of soda costs $ 16.75. The cost of p individual cans

34、of soda is $1.20 per can.（分数：1.00）A.B. C.D.解析：22.A developer has land that has x feet of lake frontage. The land is to be subdivided into lots, each of which is to have either 80 feet or 100 feet of lake frontage. If （分数：1.00）A.B.C.D. E.解析：23.Each integer from 1 to 50 whose units digit is a 3 is written on a slip of paper and placed in a box. If two slips of paper are drawn at random, what is the probability that both the numbers picked are prime?（分数：1.00）填空项 1:_ （正确答案： ）解析：