2019年9月20日的GRE数学资料预测发布，GRE数学对大多数中国考生来说虽然难度不算高，但实际上想要保证零失误拿到170满分还是颇有一定难度的。许多同学因为粗心大意而扣分没能拿到满分尤其可惜。这篇内容包括对9月20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. Quantity A: The least prime number greater than 24

Quantity B: The greatest prime number less than 28

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.

参考答案：A

题目解析：prime number = 质数，比24大的质数中最小的是29，比28小的质数中最大的是23，因此选A。

2. Quantity A：54% of 360

Quantity B：150

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.

参考答案：A

题目解析：不用去算54%*360，只要知道360的一半是180，A超过了，所以比B大，因此选A。

3. When the decimal point of a certain positive decimal number is moved six places to the right, the resulting number is 9 times the reciprocal of the original number. What is the original number?

参考答案：如果一个数的小数点右移6位，那么结果将是这个数的倒数的9倍.

设这个数为x，列出等式：1000000x=9/x，解得x=0.003

4. In the xy-plane, a quadrilateral has vertices at (–1, 4), (7, 4), (7, –5), and (–1, –5). What is the perimeter of the quadrilateral?

A. 17

B. 18

C. 19

D. 32

E. 34

参考答案：E

题目解析：笨办法是自己画坐标轴然后计算，但仔细观察四组坐标会发现各有两组的某一个值相同，因此实际构成一个长方形。最后周长为34。

5. Three pumps, P, R, and T, working simultaneously at their respective constant rates, can fill a tank in 5 hours. Pumps P and R, working simultaneously at their respective constant rates, can fill the tank in 7 hours. How many hours will it take pump T, working alone at its constant rate, to fill the tank?

A. 1.7

B. 10

C. 15

D. 17.5

E. 30

正确答案：D

题目解析：根据题目条件，设三个泵各自速率为p,r,t。列出等式：(p+r+t)*5=(p+r)*7，算出p+r=2.5t，然后设T独自工作需要时间为x，列出等式：(p+r)*7=t*x，代入上个式子的结果，x=2.5*7=17.5。