本區搜索:
Yahoo!字典
打印

[Core] 高手入黎,唔識做permutation同combination

高手入黎,唔識做permutation同combination

幫我解下

1
Peter plans to deliver 12 packages to 12 different spots
a) 3 packages will be delivered to 3 spots in the same district, so they will be delivered successively. How many delivery sequences does he have now? (Ans: 21 772 800)
b) Apart from the 3 packages mentioned in (b), there are 4 packages to be delivered to 4 spots in another district successively. How many delivery sequences does he have now? (Ans: 725 760)


2
A group of seven people queue up to enter into a museum. It is given that Cherry and Rainbow are two of them.
a) If Cherry cannot be the first one and Rainbow cannot be the last one, how many arrangements are there? (Ans:3720)


3
There are 12 differentplants in the balcony, and 5 of them are cactuses. The plants are now arrangedin a row
a.
If any two cactuses cannot be placed next to each other, how many permutation are there?(Ans: 33 868 800)
b.
If only 3 of the cactuses are placed next to each other, how many permutation are there? (Ans: 101 606400)
c.
If cactuses must be placedat the two ends, how many permutation are there? (Ans: 72 576 000)
d.
If cactuses cannot be placed at the two ends, how many permutation are there? (Ans: 152 409 600)
e.
If cactuses cannot be place at both ends at the same time, how many permutation are there? (Ans: 406 425600)


4
There are 9 different books
c) How many ways to group the books into 3 piles such that there are 3 books in each pile? (Ans: 280)
   

TOP

[隱藏]

回覆 4# 數痴夢王 的帖子

thank you so much!!

TOP

重要聲明:小卒資訊論壇 是一個公開的學術交流及分享平台。 論壇內所有檔案及內容 都只可作學術交流之用,絕不能用商業用途。 所有會員均須對自己所發表的言論而引起的法律責任負責(包括上傳檔案或連結), 本壇並不擔保該等資料之準確性及可靠性,且概不會就因有關資料之任何不確或遺漏而引致之任何損失或 損害承擔任何責任(不論是否與侵權行為、訂立契約或其他方面有關 ) 。