數學問題-排列 20points! Quick!!!!!!!
要解釋!!!!!!!!
Six people are to be seated in a row to take a picture. Two of them is a pair of couple and they have to sit next to each other, while two others are separated couple and they are not willing to sit next to each other. How many different seating arrangments are possible?
answer:
3!2!2! 4C2
=144
Why the answer is like that?
數學問題-排列 20points! Quick!!!!!!!
2011-12-12 5:03 am
回答 (1)
2012-01-09 3:41 am
✔ 最佳答案
Step 1 :一對夫婦(當一個單位) 及 2名獨立人士共 3! 種排列。
Step 2 :
一對夫婦又有 2! 種次序。
Step 3 :
一對夫婦(當一個單位) 及 2名獨立人士共 4 個空隙 , 例如 :
( ) 夫婦 ( ) 獨立 ( ) 獨立 ( )
故離異夫婦有 2! 4C2 種排列。
共 3! 2! 2! 4C2 = 144 種排列。
收錄日期: 2021-04-21 22:25:24
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20111211000051KK00790