题目：

1. AB is the diameter of the circle. If AF=BF= 3√2，and AC=5, what is the area of square BCDE?

答案：11

解析：题干求正方形BCDE的面积，根据AF=BF=3 ，三角形ABF为直角三角形，得出AB=6。根据AC=5，三角形ABC为直角三角形，得出BC²=AB²-AC²=6²-5²=11。正方形BCDE的面积=BC²=11

2. If the areas of the 4 squares are 50, 32, 18 and 12, what is the ratio of the small shaded portion to the area of the large shaded portion?(Note: Figure not drawn to scale)

A. 1:8

B. 1:6

C. 1:4

D. 1:3

E. 1:1

答案：D

解析：题干问小的黑色阴影面积/大的黑色阴影面积等于多少。小的黑色阴影面积=18-12=6，大的黑色阴

影面积=50-32=18，所以小的黑色阴影面积/大的黑色阴影面积=6/18=1:3

3. X = sum of the first 31 positive odd integers

Y = sum of the first 30 positive even integers

Column A：X - Y

Column B：30

A. The quantity in Column A is greater

B. The quantity in Column B is greater

C. The two quantities are equal

D. The relationship cannot be determined from the information given

答案：B

解析：已知公式，和=[(首项 末项)*项数]/2. 项数= [(末项-首项)/公差] 1

X=1 3 5 7 … 31=(1 31)*16/2=256

Y=2 4 6 8 … 30=(2 30)*15/2=240

所以X-Y=256-240=16. 比30小，所以选B.

4. In a group of 45 children, 60 percent of the children are boys, and 60 percent of the

children are left-handed.

Column A：Number of boys who are left-handed

Column B：8

A. The quantity in Column A is greater

B. The quantity in Column B is greater

C. The two quantities are equal

D. The relationship cannot be determined from the information given

答案：A

解析：男孩的数量为45*60%=27, 用左手的人所占的百分比为60%, 从极端情况来看即使所有非左撇子的

都是男孩，也仅有18人，即左撇子男孩至少为9人，大于ColumnB，所以选A.

5. If a truck is traveling at a constant rate of 90kilometers per hour, how many seconds

will it take the truck to travel a distance of 600 meters? (1 kilometer = 1000 meters)

A. 18

B. 24

C. 30

D. 36

E. 48

答案：B

解析：题干时速90公里的卡车需要多少秒通过600米的距离。首先换算时速90公里，90,000米/(60*60)秒

=25米/秒，所以时间=距离/速度=600/25=24秒。