171. Steven 投资，每四个月金额就会triple 总共投资１６个月，问 １６个月后的金额是之前的几倍？
参考答案：3^4
思路：

172. k与m皆是四位数 k的千位数比m的千位数大1
k的十位数比m的十位数小2
k与m的百位数与个位数皆相同
问(k/10)-(m/10)多少?
参考答案： 98
思路：

174. 十人选三人，法语老师四人，至少一人是法语老师，共几种选择?
参考答案：C(10,3)-C(6,3)
思路：

176. 前面有人提过一题大矩形里有七个正方形的，我还记得图..可是在这里很难划出来，题目给其中两个左下角square 的面积
quareA: 64 B:81，求右上角的square面积，题目不难只是看到图会有点突兀。
参考答案：
思路：解法是先利用AB边长差，再一个个推其它正方形的边长，最后推出右上角square C的边长是19 可得答案为E 361

178. X=(2/3)^(-2) Y=(-2/3)^2 Z=(2/3)^3 (Z的数字忘了…反
正一定是最小的那个) 将XYZ的关系由小到大排出来。
X>Y>Z

178.5 问 (x)^(-y)是否是整数
(1)x y都是整数
（2） x*y<0
参考答案：E
思路：

179. (1-1/5)/(1+1/5)=?
参考答案：2/3
思路：

183. car a can go 25 miles/gallon of gasoline, while car b can go 11.9 miles/gallon of gasoline. if both cars are driven 12,000 miles, how many more gallons of gasoline will car b consume than will car a? (rounded to the unit digit)
参考答案：528
思路：

184. a company increases its costs/labor charges from $50/hour to $60/hour and enhances its parts charges by 8%. a certain job requires 1.5 hours of labor charges and parts charges, and the parts charges before change were $125/hour. what percent will the total charges for this job increase?
参考答案：1/8
思路：[1.5(60-50)+125*0.08]/(50*1.5+125)

185. among the 600 attendees of a conference, 250 are republicans and 100 vegetarians. how many of the republicans are vegetarians?
1) 300 are neither republicans nor vegetarians
2) 200 republicans are not vegetarians
参考答案：D
思路：有异议，一说是B。希望大家再讨论一下

186. the average salary for company a is $3500, and the average salary for company b is $4500. how many people are in company a?
1) the average salary for company a and company b is $4200
2) there are totally 500 employees in a and b.
参考答案：C
思路：

187. ax+by+c=0. the slope is 1/2. what’s the value of b?
1) a=2;
2) c=4
参考答案：A
思路：

188. 30!/10! is expressed as the product of integers. the biggest integer is 30. what’s the smallest integer?
参考答案：11
思路：题目不是很清楚，可能是1

189. there are 500 marbles in a jar. 200 are red, 100 are blue, and 200 are green. if two marbles, one at a time without placements, are taken from the jar. what’s the possibility that both marbles are red?
参考答案：C200,2/C500,2
思路：

190. 123456789的平方，unit is the X, tenth is the Y, ask X=? Y=?
参考答案：末尾21
思路：只要乘最后2位