继续问，应该是prep的题

1. At a dinner party, 5 ppl are to be seated around a circle table. Two seating arrangement are considered different only when the position of the ppl are different relative to each other. What is the total number of difference possible seating arrangements for the group?

结果是不是  P(5,5) / 5

2. For which of the following functions is f(a+b) = f(a) + f(b) for all positive numbers a and b?

f(x) = x^2
f(x)=x + 1
f(x)=x^(1/2) + 1
f(x) = 2/x
f(x)= -3 x^9

ans. E

3.

Interval of Score                 Score Number
      50-59                                   2
      60-60                                  10
      70-79                                   16
      80-89                                   27
      90-99                                   18

The table above shows the distribution of scores on a geography quiz given to a class of 25 students. Which of the following is closet to the average quiz score for the class?

8.6
8.5
8.4
8.3
8.0

ans. c

Q1 . Two seating arrangement are considered different only when the position of the ppl are different relative to each other

这句话的意思，应该是指Ａ坐Ｂ左边或者右边，是不一样的，相对位置么，咔咔

so ans= 4!, correct

Q2 A和Ｅ，一回事吧？是不是题目抄错了？

Ｑ３这个班不止２５人吧？而且选项为啥都是８．ｘ？

Q2. A 也不对啊

f(a+b) = (a+b)^2

f(a)+f(b) = a^2 + b^2

Q3. 估计是题目错了。 

怎么觉得第一题是5！？