本文作者：雷哥GRE数学名师Helen

GRE数学考试题型包括：数量比较题、单项选择题、不定项选择题和数字填空题，以下就分题型来进行一些真题的解析。

每道题目都是5个选项，并且只有一个选项是正确的。

1.

A group of 5,000 investors responded to a survey asking whether they owned stocks and whether they owned bonds. Of the group, 20 percent responded that they owned only one of the two types of investments. If r is the number of investors in the group who owned stocks but not bonds, which of the following represents the number of investors in the group who owned bonds but not stocks, in terms of r ?

A 5,000

 B 1,000 – r

 C r – 1,000

 D 1,000r

 E (0.2)*(5,000 – r)

【答案】B

【解析】考察集合公式：S∪B=S+B-S∩B

20%*5000=S∪B-S∩B=S+B-2S∩B，即S+B-2S∩B=1000

S-S∩B=r，那么B-S∩B=1000-r

2.

Which of the following is closest to the mean of the prices of the 700 homes sold in 2012 and 2013 combined?

 A $265,000

 B $270,000

 C $275,000

 D $280,000

 E $285,000

【答案】B

【解析】图表题注意图表的描述和单位问题。

计算2012和2013结合在一起的平均数：

(410×250000+290×300000)÷700≈271000，最接近的是B选项

填空题一般是填入一个整数、小数或者分数，具体要看清楚题干对填入数字的要求。

1.

From 2011 to 2012, Jack`s annual salary increased by 10 percent and Arnie`s annual salary decreased by 5 percent. If their annual salaries were equal in 2012, then Arnie's annual salary in 2011 was what percent greater than Jack`s annual salary in 2011 ?

Give your answer to the nearest 0.1 percent. _____%

【答案】15.8

【解析】J增加10%之后与A减少5%相等，即J*(1+10%)=A*(1-5%)

解得A≈1.158J=115.8%J

2.

The first term in a certain sequence is 1, the 2nd term in the sequence is 2, and, for all integers n ≥ 3, the nth term in the sequence is the average (arithmetic mean) of the first n – 1 terms in the sequence. What is the value of the 6th term in the sequence?

Give your answer as a fraction._____/_____

【答案】3/2

【解析】可以直接计算或者找规律