>>>>>>>DS工作室<<<<<<<为您倾情整理GRE数学第一部分数学基础知识一、代数Algebra例1 比较大小：.The number of distinct positive factors of n 14比较大小例2：252因子的个数是多少？例3 比较大小：A printer numbered consecutively the pages of a book, beginning with 1 on the first page. In numbering the page, he printed a total of 204 digits.The number of pages in the book 105例4 比较大小：In a certain two-digit number,the units' digit is twice the tens' digit. 5The tens' digit例5比较大小：二、描述统计descriptive statistics例6 比较大小：某长方形的周长为40，该长方形的最大面积100例7 比较大小：空间5个点能够构成的直线数目10例8：求3，13，17的标准方差。

三、排列组合combination 、概率 probability1． 排列组合 排列计算公式： ， 组合计算公式： 。

2． 概率例9：假如世界杯比赛共有32支球队，分成8个组，每组4个队，每组前两名出线，然后成对进行淘汰赛，直至决赛决出冠军，并且淘汰队不参加比赛，从中间任选出一场比赛观看是半决赛的机会有多大？例10：有4对男女，每对中有1男1女，从每对中选出1人，选出2男2女的概率是多少？例11：有3个打字员为4家公司服务，如果4家公司各有1份文件要录入，他们只能找到这3个打字员录入，且各公司对打字员的要求是随机的。

问每个打字员都收到文件的概率是多少？例12：两个骰子，六面的值分别为1，2，3，4，5，6，投掷这两个骰子，问其中一个骰子的值比另一个的值大2的概率为多大?四、几何(Geometry)例13 比较大小：R is a point in the rectangular coordinate system and OR=5. The x-coordinate of point R 5 4.9例14 比较大小：(RS)2+(ST)2 (RT)2例15： According to the graph above, when x=3, y is most nearly:(A) -1 (B) -1/2 (C) 0 (D) 1/2 (E) 1五、文字题(Word Problem)1.利息问题(interest)单利simple interest 复利compound interest例16：If $ 8000 is invested at 6 percent simple annual interest, how much interest is earned after 3 months?例17：If $ 10,000 is invested at 10 percent simple annual interest, compound semiannually, what is the balance after 1 year?2.折扣问题(discount)例18：The price of an item is discounted by 20 percent and then this reduced price is discounted by an additional 30 percent. These two discounts are equal to an overall discount of what percent? 3. 英美常识问题GRE难题解析例1：On a certain number line, if -7 is a distance of 4 from n and 7 is a distance of 18 from n ,then n=?(A) 25 (B) 11 (C)- 3 (D) 11 (E)-11例2：The diagram represents a rectangular garden.The shaded regions are planted in flowers, and theunshaded region is a walk 2 feet wide. All angles areright angles.The sum of the areas of the 2,800 square feetshaded regions例3：The map shows the only roads that connect thefour towns and shows the distance along each road.The road distance between Austen and Seburg The road distance between Coaltown and Woodland例4：How many positive integers less than 20 are equal to the sum of a positive multiple of 3 and a positive multiple of 4?(A) Two (B) Five (C) Seven (D) Ten (E) Nineteen例5：Which of the following symbols should be substituted forto makeboth of the statements true for all integers n such that -2< n ≤3?(A) ≤ (B) < (C) = (D) > (E) ≥ 4-n 6 4-n 5例6：In a soccer league, If there were 10 teams and each team played each of the other teams 16 times, how many games did each team play?(A) 144 (B) 140 (C) 134 (D) 125 (E) 106例7：(NOTE: DRAWN TO SCALE)POPULATION OF THE U.S. AGE 55 AND OVER1984 AND PROJECTIONS FOR 1995INCOME DISTRIBUTION FOR POPULATIONOF THE U.S. AGE 55 AND OVER,1984In 1984 median income for a person in the 55~64 age category was in which of the following intervals?(A) less than ＄10,000 (B) ＄10,000~＄19,999 (C) ＄20,000~＄24,999 (D) ＄25,000~＄34,999 (E) ＄35,000~＄49,999例8：A sample of employees were tasted on data-entry skills for one hour , and the number of errors (x) they made and the percent of employees (p) making x errors were recorded as(A) 3 (B) 3.5 (C) 4 (D) 4.5 (E) It cannot be determined from the information given.例9：d=7.56872 and D is the decimal expression for d rounded to the nearest thousandth. The number of decimal place where d and D differ4例10：In a certain country, a person is born every 3 seconds and a person dies every 10 seconds. Therefore, the birth and death rates account for a population growth rate of one person every例11：Of the positive integers that are multiples of 30 and are less than or equal to 360, what fraction are multiples of 12?(A) 1/6 (B) 1/5 (C) 1/3 (D) 2/5 (E) 1/2例12：The figure shows a large square formed by fitting three L-shaped tiles and one small square tile together . If a rectangular floor 10 feet by 12 feet is to be tiled in large squares of this design, how many L-shaped tiles will be needed?(A) 810 (B) 405 (C) 270 (D) 135 (E) 45例13：The daily rate for a hotel room that sleeps 4 people is $39 for one person and x dollars for each additional person. If 3 people take the room for one day and each pays $21 for the room, what is the value of x?(A) 6 (B) 8 (C) 12 (D) 13 (E) 24例14：A positive integer with exactly two different divisors greater than 1 must be (A) a prime (B) an even integer (C) a multiple of 3(D) the square of a prime (E) the square of an odd integer例15：x>z, y>z x + y z例16：x>y and xy ≠0 (x + y)/x (x + y)/y例17：2AF=AB=BD=DE=AEThe sum of the area of triangular region ABF and area of triangularregion CDE The area of rectangular region BCEF例18：Each of the following numbers has two digits blotted out. Which of the numbers could be the number of hours in x days, where x is an integer?8inches 8inches(A)25,06 (B)50,26 (C)56,02 (D)62,50 (E)65,20例19：There are 1200 represents to a poll, each favoring their preference for candidates A, B, and C. 54% favored A, 48% favored B, and 42% favored C, and there is 30% favored both A and B. What’s the largest possible number of represents favoring c, but not C&B, nor C&A?(A)25% (B)30% (C)28% (D)38% (E)40%例20：Out of 100 ladies attending the church fete, 85 had a white handbag; 75 had black shoes;60 carried an umbrella; 90 wore a ring, How many ladies must have had all four items?(A)15 (B)35 (C)5 (D)10 (E)25例21：In an insurance company, each policy has a paper record and an electric record. For thosepolicies having incorrect paper record, 60% also having incorrect electric record; For those policies having incorrect electric record, 75% also having incorrect paper record. 3% of all policies have both incorrect paper and incorrect electric record. If we randomly pick out one policy, what’s the probability that the one having both correct paper and correct electric rec ord?(A)0.80 (B)0.94 (C)0.75 (D)0.88 (E)0.92例2212345are p1,p2,p3,p4,p5 , respectively, then the expected value is defined as a1 p1+ a2 p2+a3 p3+ a4 p4+ a5p5.For the values and their corresponding probabilities in the table above, what is the expected value?(A)350 (B)320 (C)300 (D)270 (E)250例23：The standard deviation of the sample measurements 0, 2, 4, 6, and 8 The standard deviation of the sample measurements 1, 3, 5, 7, and 9例24：What is the total number of different 5-digit numbers that contain all of the digits 2, 3,4,7and 9 and in which none of the even digits occur next to each other?(A)72 (B)100 (C)120 (D)60 (E)48例25：Water is to be poured at a rate of 2.5 gallons per minute into a 500-gallon tank that initially contains 50 gallons of water.The percent of the tank's capacity that will befilled 1 hour after water begins to be poured in60 percent例26：In the figure, if x, y, and z are integers suchthat x<y<z, then the least and the greatest possiblevalues of x+z are(A)59 and 91 (B)69 and 135 (C)91 and 178(D)120 and 135 (E)120 and 178例27：The figure shows the dimensions ofrectangular box that is to be completelywrapped with paper. If a single sheet ofpaper is to be used without patching, thenthe dimensions of the paper could be(A)17 in by 25 in (B)21 in by 24 in (C)24 in by 12 in(D)24 in by 14 in (E)26 in by 14 in例28：In the table, what is the least number of tableentries that are needed to show the mileagebetween each city and each of the other five cities?(A)15 (B)21 (C)25 (D)30 (E)36例29：A store currently charges the same price for each towel that it sells. If the current priceof each towel was to be increased by $1, 10 fewer of the towels could be bought for $120, excluding sales tax. What is the current price of each towel?(A)$ 1 (B)$ 2 (C)$3 (D)$ 4 (E)$ 12GRE数学常用符号及术语一.数学中常用符号+: plus X:multiply-:subtract÷:divideV~:square root|...|:absolute value=: is equal to=/=: is not equal to>: is greater than<: is less than//:is parallel to_|_:is perpendicular to>=:is greater than or equal to(或no less than)<=:is less than or equal to(或no more than)二.表达相应数目的前缀1:uni-,mono- 2:bi-,du-,di- 3:tri-,ter-, 4:tetra-,quad-, 5:penta-,quint, 6:hex-,sex-, 7:sept-,hapta-, 8:oct, 9:enn-, 10:dec-,deka-,三.数学中常用单词术语abscissa 横坐标absolute value 绝对值acute angle 锐角adjacent angle 邻角addition 加algebra 代数altitude 高angle bisector 角平分线arc 弧area 面积arithmetic mean 算术平均值（总和除以总数）arithmetic progression 等差数列（等差级数）arm 直角三角形的股at 总计（乘法）average 平均值base 底be contained in 位于...上bisect 平分center 圆心chord 弦circle 圆形circumference 圆周长circumscribe 外切，外接clockwise 顺时针方向closest approximation 最相近似的combination 组合common divisor 公约数，公因子common factor 公因子complementary angles 余角（二角和为90度）Composite number 合数（可被除1及本身以外其它的数整除）concentric circle 同心圆cone 圆锥（体积＝1/3*∏*r*r*h）congruent 全等的consecutive integer 连续的整数coordinate 坐标的cost 成本counterclockwise 逆时针方向cube 1.立方数2.立方体（体积＝a*a*a表面积＝6*a*a）cylinder 圆柱体decagon 十边形decimal 小数decimal point 小数点decreased 减少decrease to 减少到decrease by 减少了degree 角度define 1.定义 2.化简denominator 分母denote 代表，表示depreciation 折旧distance 距离distinct 不同的dividend 1.被除数 2.红利divided evenly 被除数divisible 可整除的division 1.除 2.部分divisor 除数down payment 预付款，定金equation 方程equilateral triangle 等边三角形even number 偶数expression 表达exterior angle 外角face(立体图形的）某一面factor 因子fraction 1.分数 2.比例geometric mean 几何平均值（N个数的乘积再开N次方）geometric progression 等比数列（等比级数）have left 剩余height 高hexagon 六边形hypotenuse 斜边improper fraction 假分数increase 增加increase by 增加了increase to 增加到inscribe 内切，内接intercept 截距integer 整数interest rate 利率in terms of... 用...表达interior angle 内角intersect 相交irrational 无理数isosceles triangle 等腰三角形least common multiple 最小公倍数least possible value 最小可能的值leg 直角三角形的股length 长list price 标价margin 利润mark up 涨价mark down 降价maximum 最大值median, medium 中数（把数字按大小排列，若为奇数项,则中间那项就为中数，若为偶数项，则中间两项的算术平均值为中数。