GRE数学经典错题 1RESULTS OF A USED-CAR AUCTIONFigure 7For die large cars sold at an auction that is siuivnarized in tl)e table above, what was tl)e average sale price per car?答案：6000错因：单位!A merchant made a profit of S5 on the sale of a sweater that cost the merchant $15. What is tlieprofit expressed as a percent of the merchant's cost?Give your answer to the nearest whole percent.33%错因：最近的整数。

319. For a certain probability experiment, the probability that event A will occur is L and the… 1 .probability that event B will occur is —. Which of the following values could be theprobability that the event A U 8 (that is, the event A or B, or both) will occur?Indicate all such values.LM 74BC画图4Of the 20 lightbulbs in a box, 2 are defective. An ins|>ector will select 2 lightbulbs simultaneously and at random from the box. What is the probability that neither of the I ightbu lbs selected will be defective?C18,2/C20,25注意表达A random variable Y is normally distributed with a mean of200 and a standard deviation of 10.Quantity A(Juantily B9. The probability of the event 1® (B) CD (©that the value of Y is 6greater than 220GO ON TO THE NEXT PAGE ■正态分布有一个图：平均值200，标准差10，则超过220的概率2%,小于1/67.13. A list of numbers has a mean of 8 and a standard deviation of 2.5. If x is a nuniber in the listthat is 2 standaid deviations above the mean, what is the value of Jt ?8+2*2.5=132 standard deviations 两倍标准差8.9. By weight, liquid A makes up 8 percent of solution R and 18 percent of sohinon S. If 3grams of solution R are mixed with 7 grams of solution S, liquid A accounts for what percent of the weight of the resulting ion?10^13%15%19%26%8.(3*8%+7*18% ) /10=15%错因：题目没看懂A组成了R的8% 9.D10.histogram 直方图In the course of an experiment, 95 measurements were recorded, and all of themeasurements were integer. The 95 measurements were then grouped into 7 measurementintervals. The graph above shows the frequency distribution of the 95 measurements bymeasurement interval.Quantity A Quantity BThe average (arithmetic The median of the 95 応)(B) ①)①) mean) of the 95measurementsmeasurements都取小的最小平均值：(1*15+6*35+11*15+16*13+21*10+26*5+31*3)二median of the 95 measurements 这95 个数的中位数：6-10或者看看也能看岀来注意：这种柱状图的解法10.The random vaiiable X is normally distributed. The values 650 and 850 are at the 60th and 90th percentiles nf the diMribution of X, respectively.Quantity AQuantity B5. The value at the 75th750(T) (E) © ®percentile of the distribution of XSet S consists of all positive integers less than 81 that are not equal to the square of an integer.Quantity AQuantity B错音：表达没看懂S 里面的个数=72the number in S: S 里面的数 12.14. Let S be the set of all positive integers n such that K 2 is a multiple of both 24 and 108. Which of thefollowing integers are divkan? of every integer in S ?Indicate all such integers.公倍数 a multiple ofS 是正整数，S 里的数为36的倍数 AC11.6. The number of integers in set S72® ® © ©囚回回回2 4 6 210-12 岀自OGP191 13 P34512. In a graduating class of 236 students, 142 took algebra and 121 took chemistry. What is th^greatest DossjhL、rmmhw cf students that could have taken both algebra andchemistry?1316. If(2")(5】7)" expressed as a terminating decimal how many nonzero digiis will the decimalhave?OneTwoFourSixEleven问有多少非0的位数0.000...64 选B14VARIATION IN THE .AMOUNT OF CAFFEINE IN COMMON BEVERAGES AND DRL咬Amount of Caffeine (milligrams) 0 25 5)75 100 125 150 175 200Coffee Decaffeinated coffeePercchted coffeeDrip-breued coffeeInstant coffeeZl匚11Other beve*眺 $Brewed teat&ACccaaCaffeinated soft drinJuLn1JDrugs Weight-loss drugs, diuretics,and stimulantsFain nelievei*sCold/allerg)r I'emedies匚----- 1 ---- 1 ---- 1 ---1S&urce： Fc>^d and Dni^ AdinMislfaii&n•Based on 5-ounee cups of coffee, lea, and cocoa; 2-ounce cups of soft drinks; and single doses of drugs.18. For how many of the 11 categories of beverage*; And drugs liyled in the graph can the amount of caffeine- in the give#sen»ing size be le ■曙 than SO miUigram&?答案9,比50少的。

1523. Which of the following statements indiudually provddefs) sufficient additional information to deteiTninethe area of triangle ABC above?Indicate all such statements.DBC is an equilateral triangle. ABD is an isosceles tiiangle.The length of fiC is equal to the length of AD. The length of BC is I □_ The length of AD 招 10.答案AD16 absolute value 绝对值 机经的题目2. s, t, and u are integers, and 102 s < t < u 2 20Quamiw A: u Ouamity B: 11A. Quantity A is greate .B. Quantity B is greater.C. The two quantities are equalD. The relationship cannot be determined from the information given.纯粹粗心 D12.A B C D E F G回回©回The length of AB is 10、气——4——♦ ---* ----- + --- ♦——♦——*——♦- > ----- ►-4-3-2-101234The average (arithmetic mean) of the coordinates of the 7 labeled points on the number line is how much greater or less than the median of the coordinates of the 7 labeled points?A.4/7 greaterB.3/7 greaterC.1/2 greaterD.3/7 lessE.4/7 lessE这题易错。