GRE数学考试的练习题分享

　　2019 年12月28日场次gre数学预测发布，详细内容包括对 12 月 28 日 GRE 数学各大高频考点题型的具体讲解和解题思路剖析，确保考生不在简单数学部分意外失分，顺利拿到高分满分！
　　 题目1. In a probability experiment, G and H are independent events. The probability that G will occur is r, and the probability that H will occur is s, where both r and s are greater than 0.
　　Quantity A：the probability that either G will occur or H will occur, but not both
　　Quantity B：r s-r*s
　　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.
　　正确答案：B
　　题目解析：G 事件与 H 事件互相独立，G 事件概率为 r, H 事件概率为 s，求两事件其中之一发生的概率。
　　只发生 G 事件：r* ( 1-s )
　　只发生 H 事件：s* ( 1-r )
　　相加可得 r s-2*r*s，小于 Quantity B，因此选 B。
　　2. The area of circle W is 16* π and the area of circle Z is 4* π . What is the ratio of the circumference of W to the circumference of Z?
　　A. 2 to 1
　　B. 4 to 1
　　C. 8 to 1
　　D. 16 to 1
　　E. 32 to 1
　　正确答案：A
　　题目解析：根据圆形面积公式，可知两圆的半径比例为 2:1，然后根据周长公式计算，其州长比例也为 2:1。所以选 A。
　　 3. The interior dimensions of a rectangular tank are as follows: length 110 centimeters, width 90 centimeters, and height 270 centimeters. The tank rests on level ground. Based on the assumption that the volume of water increases by 10 percent when it freezes, which of the following is closest to the maximum height, in centimeters, to which the tank can be filled with water so that when the water freezes, the ice would not rise above the top of the tank?A. 230
　　B. 235
　　C. 240
　　D. 245
　　E. 250
　　正确答案：D
　　题目解析：已知水箱长宽高数据，和水结冰时会上升 10% 高度的推论，问水箱里可以装多少水，其结冰时也不会超过水箱高度。设为 x，列出 1.1x=270，x 约等于 245，所以选 D。

　　4. In a certain sequence of numbers, each term after the first term is found by multiplying the preceding term by 2 and then subtracting 3 from the product. If the 4th term in the sequence is 19, which of the following numbers are in the sequence? Indicate all such numbers.
　　A. 5
　　B. 8
　　C. 11
　　D. 16
　　E. 35
　　正确答案：A C E
　　题目解析：一项设为 x，根据题目条件可知第二项 2x-3，第三项 2 ( 2x-3 ) -3=4x-9，第四项依次类推为 8x-21。接下来根据第四项 =40 算出 x=5，代入前五项，分别算出 5,7,11,40,35。其中符合条件的选项为 ACE。
　　5.
　　The quadrants of the xy-plane are shown in the figure above. In the xy-plane, line m ( not shown ) has a positive slope and a positive x-intercept. Line m intersects which of the quadrants? Indicate all such quadrants
　　A. Quadrant I
　　B. Quadrant II
　　C. Quadrant III
　　D. Quadrant IV
　　正确答案：A C D
　　题目解析：本题关键在于看懂抽象描述。问直线 m 经过哪几个象限。条件 positive slope 可知 m 大致上是从左下往右上的斜线，那么第二和第四象限必然有一个不经过或者两个都不经过，条件 positive x-intercept 表明 m 和 x 轴的正数侧也就是右侧相交，那么 m 经过象限就是 1,3,4，所以选 ACD。