咁多位,我又黎問probability啦~T^T

Q::Two 16 seater mini buses.A and B, are awaiting at a station. A and B have already had 11 and 12 seats occupied respectively. Each passenger selects A with probability 4/7 and selects B with probability 3/7.Find the probability that A is filled up first.

A:0.5272

見到D英文而經想死=v=

probability

唔識計呀..........

Hint:
The probability distribution requires 5 more passengers for A while there are 3, 2, 1 or 0 more passengers in B. The orders of boarding A and B are not important except the last one, who must board bus A. Therefore (n-1)Cr is used.




If you still cannot get the answer, you can check this.
(presentation for answer (e.g. "Let ... be ...") is omitted)

Bus A: 16-11=5
bus B: 16-12=4
PE=P(5A)+P(4A1B+last one is A)+P(4A2B+1A)+P(4A2B+1A)+P(4A3B+1A)
PE=(4/7)^5+5C4*(4/7)^5*(3/7)+6C4*(4/7)^5*(3/7)^3+7C4*(4/7)^5*(3/7)^3
PE=0.5272

嘩....恐怖數學！

好驚呀! 呢度真係卧虎藏龍~

請問您系讀M1定M2呀.......
呢d系core定系......

孖吉 發表於 2011-10-12 09:07
Hint:
The probability distribution requires 5 more passengers for A while there are 3, 2, 1 or 0 mor ...

孖吉 你真係我恩人T^T
好多謝你Dtips

chingyi724  勁人呀~好多勁人呀!!!  發表於 1 分鐘前

係我外子所為

sorry , 佢唔應該咁答 ~ 答案太明顯了 ~ 因為佢係數痴, 佢好鍾意計你 d 數, 佢計完仲好開心攞埋我 a/c 答埋 ~ sorry sorry~

Reply點評：當我＂哦＂佢做咩去做數時，佢話：我無比唒答案。究竟佢列左咩我眞係唔知

gunbuster363  咩5c4 7c4??  發表於 7 小時前

~ sorry , 我本人除了 1-100 同 a-z, 以上的全不懂 ~
~ 我外子上來查案, 順便答埋條數 ~

sorry sorry , 打攪哂

Karine 發表於 2011-10-12 19:07
chingyi724  勁人呀~好多勁人呀!!!  發表於 1 分鐘前

係我內子所為

haha~唔洗講sorry wo~
我都好開心孖吉可以教我解決問題
大家入黎交流下姐

回:M1呀~
我都系，好耶，有咩唔明有人問~~~

Karine 發表於 2011-10-12 19:08
gunbuster363  咩5c4 7c4??  發表於 7 小時前

~ sorry , 我本人除了 1-100 同 a-z, 以上的全不懂 ~

5c4,7c4呢D其實係1個數學嘅表達方法, formula為nCr
以7c4為例,即係有7個人,隨意抽4個人(1定要係randomly),可以有幾多個組合,當中嘅c係combination(組合)
當然,除左nCr之外,仲有1個叫做nPr,P=permutation(排列)
nCr同nPr好唔同嫁~不過呢2個嘅應用性好高,學黎旁下身都唔錯

marcolmh929 發表於 2011-10-12 19:14
回:M1呀~
我都系，好耶，有咩唔明有人問~~~

M1 calculus 嗰part好好玩好正!!(識唔識係另1回事)

我宜家岩岩學左Pascal's triangle,我覺得有少少難...........
請問您用邊本書ga??

marcolmh929 發表於 2011-10-12 19:19
我宜家岩岩學左Pascal's triangle,我覺得有少少難...........
請問您用邊本書ga??

我用new century mathematics m1嫁

cherrylwy 發表於 2011-10-12 17:56
好驚呀! 呢度真係卧虎藏龍~

相比起我只係1條蟲

marcolmh929
唔識米好似我咁打上黎連答案,1齊研究下