GRE-Math+Review及答案解析.doc

1、GRE-Math+Review 及答案解析(总分：75.00，做题时间：90 分钟)一、BNumbers and Ope(总题数：9，分数：50.00)These exercises are designed to help you apply the mathematics concepts just covered. They are not in GRE format, but should help you to identify your areas of strength and weakness.Basic OperationsThese questions will test

2、your knowledge of operations using integers, real numbers, fractions, and decimals.Insert the correct operator in the blanks below.（分数：10.00）(1).108 _ 9=12（分数：1.00）_(2).7 _ 2=3.5（分数：1.00）_(3).（分数：1.00）_(4).When 5 consecutive odd integers, each greater than 34 are added, what is the smallest possible

3、 sum?（分数：1.00）_(5).What is the Lowest Common Denominator of （分数：1.00）_(6).（分数：1.00）_(7).3(27+2-3)= _（分数：1.00）_(8).（分数：1.00）_(9).231.2-198.7= _（分数：1.00）_(10).（分数：1.00）_Squares and Square RootsThese questions will test your knowledge of operations using square roots.Solve the following problems.（分数：5.

4、00）(1).72= _（分数：1.00）_(2).（分数：1.00）_(3).Express 33 as a square: _（分数：1.00）_(4).72-32=（分数：1.00）_(5).（分数：1.00）_ExponentsThese questions will test your knowledge of operations using exponents.Fill in the blanks below with the correct number.（分数：5.00）(1).2 raised to the power of _ =8（分数：1.00）_(2).33=_（分

5、数：1.00）_(3).2223=_（分数：1.00）_(4).125=59_（分数：1.00）_(5).(24)2=_（分数：1.00）_Scientific NotationThese questions will test your knowledge of operations using scientific notation.Fill in the blanks below with the correct number.（分数：5.00）(1).423,700,000=4.23710 to the power of _（分数：1.00）_(2).3.76105=_（分数：1.00

6、3).(2.50104)(1.25103)= _（分数：1.00）_(4).6.4710-5=_（分数：1.00）_(5).9.832104=_（分数：1.00）_Mean, Median, and ModeThese questions will test your knowledge of operations involving mean, median, and mode.Fill in the blanks below with the correct number.（分数：5.00）(1).Ann scored 88, 93, 84, and 99 on 4 tests. W

7、hat is her mean test score?（分数：1.00）_(2).What is the mode of the data given below?7,3,6,7,5,8,9,7（分数：1.00）_(3).What is the median of the data given below?8, 13, 9, 8, 15, 14, 10（分数：1.00）_(4).Jordan had 3 hits in his first 4 baseball games and 4 hits in his next 4 games. What is the average number of

8、 hits Jordan had in all of his games?（分数：1.00）_(5).What is the median of the data given below?80, 19, 82, 15, 72, 3（分数：1.00）_Ratio, Proportion, and PercentThese questions will test your knowledge of operations involving ratio, proportion, and percent.Answer the following questions.（分数：5.00）(1)._ is

9、30% of 20.（分数：1.00）_(2).（分数：1.00）_(3).As an analyst for the Department of Natural Resources, you analyze samples of river water. A 2-liter sample of water contained about 24 of a particular organism and a 4-liter sample of water contained about 48 such organisms. At this rate, how many of the organi

10、sms would you expect to find in a 10-liter sample of water from the same river?（分数：1.00）_(4).If 20% of x equals 16, then x=_（分数：1.00）_(5).Jim scored 95 points in 5 basketball games for his school. At this rate, how many points will he have scored by the end of the 12-game season?（分数：1.00）_Absolute V

11、alueThese questions will test your knowledge of operations involving absolute value.Solve the following equations.（分数：5.00）(1).If x=-8, what is the value of |x-6|?（分数：1.00）_(2).Solve |4x-6|=10 for x.（分数：1.00）_(3).|-15|6|=_（分数：1.00）_(4).Solve |6x+8|=|3x-7| for x.（分数：1.00）_(5).（分数：1.00）_Simple Probabi

12、lity and OutcomesThese questions will test your knowledge of operations involving simple probability and outcomes.Answer the following questions.（分数：5.00）(1).If you roll a single 6-sided die, what is the probability that you will roll an odd number?（分数：1.00）_(2).A company knows that 2.5% of the CD p

13、layers it makes are defective. If the company produces 300,000 CD players, how many will be defective?（分数：1.00）_(3).When flipping a coin, what is the probability that it will land on tails four times in a row?（分数：1.00）_(4).If the probability that Dave will go to class is 0.7, what is the probability

14、 that he will not go to class?（分数：1.00）_(5).A bowl contains 20 marbles (8 blue, 6 red, 3 green, 2 yellow, and 1 orange). If you reach in and choose one marble at random, what is the probability that it will be red?（分数：1.00）_Factors and MultiplesThese questions will test your knowledge of operations

15、involving factors and multiples.Answer the following questions.（分数：5.00）(1).A certain integer n is a multiple of both 5 and 9. Must n be a multiple of 15?（分数：1.00）_(2).What are the common factors of 7 and 42?（分数：1.00）_(3).What is the Greatest Common Factor of 48 and 72?（分数：1.00）_(4).What is the Leas

16、t Common Multiple of 30 and 40?（分数：1.00）_(5).What is the greatest positive integer x such that 2x is a factor of 1210?（分数：1.00）_二、BAlgebra and Fun(总题数：5，分数：25.00)These exercises are designed to help you apply the mathematics concepts just covered. They are not in GRE format, but should help you to i

17、dentify your areas of strength and weakness.Linear Equations with One VariableThese questions will test your knowledge of linear equations involving one variable.Solve the following equations.（分数：5.00）(1).3x-17=46. Solve for x.（分数：1.00）_(2).（分数：1.00）_(3).If x=15, then 4x- _ =42（分数：1.00）_(4).Two trai

18、ns running on parallel tracks are 600 miles apart. One train is moving east at a speed of 90 mph, while the other is moving west at 75 mph. How long will it take for the two trains to pass each other?（分数：1.00）_(5).3(x-4)=5x-20. Solve for x.（分数：1.00）_Polynomial Operations and Factoring SimpleQuadrati

19、c EquationsThese questions will test your knowledge of operations involving polynomial operations and factoring simple quadratic equations.Solve the following equations.（分数：5.00）(1).For x=4, 3x2-5x+9=_（分数：1.00）_(2).(5x3+3x-12)-(2x3-6x+17)=_（分数：1.00）_(3).(4x2+2x)(x-6)=_（分数：1.00）_(4).What are the solu

20、tion sets for x2+2x-48?（分数：1.00）_(5).(x-4) and (2x+3) are the solution sets for what equation?（分数：1.00）_Systems of EquationsThese questions will test your knowledge of operations involving systems of equations.Solve the following systems of equations.（分数：5.00）(1).x-2y=14x-4y=-8（分数：1.00）_(2).4x-2y=6-

21、6x+5y=7（分数：1.00）_(3).3x-y= 184x=24-6y（分数：1.00）_(4).8(y+x)=124x-3y=-22（分数：1.00）_(5).4x-y=633y+x=6（分数：1.00）_Linear Inequalities with One VariableThese questions will test your knowledge of operations involving linear inequalities with one variable.Answer the following questions.（分数：5.00）(1).For-5-x15,

22、 x=_（分数：1.00）_(2).For which values of x is 6x-34x+5?（分数：1.00）_(3).If x=7, then is 3x+7 greater than or less than 5x-6?（分数：1.00）_(4).For which values of x is 2x-5-3x+20?（分数：1.00）_(5).Solve for x: -4x+318（分数：1.00）_FunctionsThese questions will test your knowledge of operations involving functions.Answ

23、er the following questions.（分数：5.00）(1).For the function f(x)=x2-4x+8, what is the value of f(6)?（分数：1.00）_(2).If f(x)=x2, find f(x+1).（分数：1.00）_(3).If the function f(x)=x+2, and the function g(x)=3x, what is the function gf(x)?（分数：1.00）_(4).For the function what is the value of f(2)?（分数：1.00）_(5).F

24、or the function f(x)=x2+x, what is the value of f(-5)?（分数：1.00）_GRE-Math+Review 答案解析(总分：75.00，做题时间：90 分钟)一、BNumbers and Ope(总题数：9，分数：50.00)These exercises are designed to help you apply the mathematics concepts just covered. They are not in GRE format, but should help you to identify your areas of s

25、trength and weakness.Basic OperationsThese questions will test your knowledge of operations using integers, real numbers, fractions, and decimals.Insert the correct operator in the blanks below.（分数：10.00）(1).108 _ 9=12（分数：1.00）_正确答案：()解析：In order for 12 to be the result of this operation, you must d

26、ivide 108 by 9. Insert the symbol in the blank.(2).7 _ 2=3.5（分数：1.00）_正确答案：()解析：To reach an answer of 3.5, you must divide 7 by 2. Insert the + symbol in the blank.(3).（分数：1.00）_正确答案：()解析：One way to solve this problem is to look for the Lowest Common Denominator (LCD). The smallest number that both 4 and 8 divide evenly into is 8, so the fraction does not need to be changed. The fraction is e