一个数学问题,请专家帮助

At a dinner party, 5 people are to be seated around a circular table. Two seats arrangements are considered different only when the position of the people are different relative to each other. what is the number of different possible seating arrangements for the group?

A. 5   B10.   C 24...D 120  

答案是C

题目对于不同排法的定义是什么意思？Two seats arrangements are considered different only when the position of the people are different relative to each other

题目对于不同排法的定义是什么意思

means 1  2  3  4  5        =     1  2  3  4  5

      a  b  c  d  e              e  a  b  c  d

1,2,3,4,5 is the order of the place (should be around a table, but cannot draw a circle here)

the answer = 4*3*2*1

when a position is fixed, the rest four places have 4, 3, 2, and 1 alternatives, respectively.

the reason ETS's 题目对于不同排法的定义是什么意思 is to simplify the question, because if consider seat position too, this problem will be a little bit more works, which is a disaster for American and Canadian students

谢谢,可是他和普通的P(5,5)的排列有什么区别呢?因为是圆桌所以不一样吗?