Board logo

標題: [Core] 有冇人識計 [打印本頁]

作者: aryan06    時間: 2019-6-2 05:01 PM     標題: 有冇人識計

9 students will be placed randomly on 13 chairs in a row, find the probability that no two empty chairs will be adjacent.

答案係42/143
有冇人可以解答,thanks




作者: hazzalfred    時間: 2019-6-2 06:11 PM

(10C4)/(13C9)
當將4個empty seats放喺9個人之間  _為空位
_1_2_3_4_5_6_7_8_9_
所以10個空位裡面放4 ,10C4
13C4就喺total number of ways
作者: aryan06    時間: 2019-6-2 06:40 PM

Thanks so much








歡迎光臨 小卒資訊論壇 (http://www.lsforum.net/board/) Powered by Discuz! 6.0.0