官方题库全新解密 GRE数学2道经典例题讲解
- 2015年07月29日11:07 来源：小站整理
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GRE数学考试中的一些经典题型是常考的内容，对这些题型的把握是做好GRE数学的关键。
经典例题1：morethantwice
Each employee of a certain company is in either Department X or Department Y, and there are more than twice as many employees in Department X as in Department Y. The average (arithmetic mean) salary is $25,000 for the employees in Department X and is $35,000 for the employees in Department Y. Which of the following amounts could be the average salary for all of the employees in the company?
Indicate all such amounts.
A $26,000
B $28,000
C $29,000
D $30,000
E $31,000
F $32,000
G $34,000
本题我们要注意到题目中的more than twice的字眼，我们当做twice算的时候，结果是(25000*2+35000)/3约等于28333，因为有more than，所以选的答案要么是比前面这个数大，要么小，又由于more的是X部门的，那么肯定会将平均工资给拉低了，因此，选比前面那个数小的答案，AB都可以了。
经典例题2：dollar amount
If the dollar amount of sales at Store P was $800,000 for 2006, what was the dollar amount of sales at that store for 2008 ?
A $727,200
B $792,000
C $800,000
D $880,000
E $968,000
直接算，800000*(1+10%)*(1-10%)=792000，即B
2)At Store T, the dollar amount of sales for 2007 was what percent of the dollar amount of sales for 2008 ?
Give your answer to the nearest 0.1 percent.___________%
直接算，1/(1-8%)=108.7%(约等于)
3)Which of the following statements must be true?
Indicate all such statements.
A For 2008 the dollar amount of sales at Store R was greater than that at each of the other four stores.
B The dollar amount of sales at Store S for 2008 was 22 percent less than that for 2006.
C The dollar amount of sales at Store R for 2008 was more than 17 percent greater than that for 2006.
本题A选项一看到就可以排除了，涉及到两个店的绝对量的比较，这个不确定，没有告诉绝对值。B选项是把两个增长的比例简单地算术相加。肯定错了。所以C肯定是对的了。。通过计算也的确是对的。
既然是经典例题就需要大家在备考中勤于练习，在考试中遇到类似的题型才会轻松拿下。
TIPS：GRE数学备考心得：基础扎实才能拿高分
在专注于解决最高难度的GRE题目前，先确保你已经完全掌握了以下基础知识点：解方程式、常用公式、百分比变换、分数相加相乘。还有更进一步的比如：简化带分数的方程式、小数与百分比转换、分数与小数转换、计算圆的面积和周长、多项式的计算和其他基础的初高中数学知识。
