12月4日的GRE考试马上就要开始了,同学们准备的怎么样了呢?出国留学网GRE栏目为您整理12月4日GRE数学小范围机经预测,希望能有所帮助哦!
题目
1. If k is an integer and 121 < k^2 < 225,then k can have at most how many values?
A. 3
B. 4
C. 5
D. 6
E. 7
答案:D.
解析:k可以是12,13,14,-12,-13,-14.
2. Runner A ran 4/5 kilometer and Runner B ran 800 meters.
Quantity A: The distance that A ran
Quantity B: The distance that B ran
A. Quantity A is greater.
B. Quantity B is greater.
C. The two quantities are equal.
D. The relationship cannot be determined from the information given.
答案:C
解析:Quantity A=(4/5)*1000=800=Quantity B。
3. x < y < z,
Quantity A: (x + y + z)/3
Quantity B: y
A. Quantity A is greater.
B. Quantity B is greater.
C. The two quantities are equal.
D. The relationship cannot be determined from the information given.
答案:D
解析:已知条件太少,AB大小都可以根据不同数据列出可能答案,因此无法判断准确唯一解,选D。
4. A reading list for a humanities course consists of 10 books, of which 4 are biographies and the rest are novels. Each student is required to read a selection of 4 books from the list, including 2 or more biographies. How many selections of 4 books satisfy the requirements?
A. 90
B. 115
C. 130
D. 144
E. 195
答案:D
解析:10本书中,4本biographies,6本novel。現在biographies要选2本以上。
思路1:正面解法
所以可能情形有bio选2本(配nov选2)+bio选3本(配nov选1本)+bio选4本(配nov选0本)。
即(C4取2乘C6取2)+(C4取3乘C6取1)+(C4取4乘C6取0)=115
思路2:反向解法
用全部扣除bio选0本(配nov选4)再扣bio选1本(配nov选3)
利用C10取4-C4取0*C6取4-C4取1*C6取3 = 210 - 15 - 80 = 115
5. In a graduating class of 236 students, 142 took algebra and 121 took chemistry. What is the greatest possible number of students that could have taken both algebra and chemistry?
答案:121
解析:可能不少人会用142+121-236=27的思路来解题,但问题是least possible number,同时也没有表明只能选两门课,因此有可能还有其他課可选,因此正确答案是眼前两个交集的最大数,也就是142和121取最小数,121个学chemistry的都选了algebra。所以为121。
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