2015年新GRE數(shù)學(xué)預(yù)測(cè)題及答案解析

GRE考試取得高分，除了掌握一些答題技巧，再加上不斷地練習(xí)，沒(méi)有其他捷徑。為了能給大家提供一些練習(xí)的機(jī)會(huì)，新通小編跟大家分享2015年9月GRE數(shù)學(xué)預(yù)測(cè)題，希望大家好好珍惜。

預(yù)測(cè)一：
       1. In an insurance company, each policy has a paper record and an electric record. For those policies having incorrect paper record, 60% also having incorrect electric record; For policies having incorrect electric record, 75% also having incorrect paper record. 3% of all policies have both incorrect paper and incorrect electric records. If we randomly pick out one policy, what’s the probability that the one having both correct paper and correct electric records?
　　(A) 0.80 (B) 0.94 (C) 0.75 (D) 0.88 (E) 0.92
　　解：設(shè)總數(shù)為x，設(shè)incorrect paper record有y, incorrect electric record有z，則：
　　x•y•60%=3%•x y=5%
　　x•z•75%=3%•x z=4%
　　則，兩者至少有一個(gè)錯(cuò)誤的百分比為5%+4%-3%=6%，所正確答案為94%
　　2. There are 1200 respondents 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 respondents favoring C, but not C&B, nor C&A?
　　(A) 25% (B) 30% (C) 28% (D) 38% (E) 40%
　　解：A和B的并集為：54%+48%-30%=72%，所C為28%.
預(yù)測(cè)二：
　　1. The probability that event A will occur is 0.5. The probability that event B will occur is 0.4. The probability that event A or B will occur is 0.8.
　　Column A：Probability that A and B both occur
　　Column B：0.1
　　A. The quantity in Column A is greater
　　B. The quantity in Column B is greater
　　C. The two quantities are equal
　　D. The relationship cannot be determined from the information given
　　2. Yesterday, at a certain school, the ratio of boys to girls was 1 to 3. Today, an equal number of boys and girls joined the school. The number that joined was greater than zero and no students left.
　　Column A: Ratio of boys to girls now
　　Column B: 1/3
　　A. The quantity in Column A is greater
　　B. The quantity in Column B is greater
　　C. The two quantities are equal
　　D. The relationship cannot be determined from the information given
GRE數(shù)學(xué)參考答案：1C 2A
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