1,An ordinary deck of 52 cards is dealt, 13 each, to four players at random. what is the probability that each player receives 13 cards of the same suit?
2.A 4-digit number is selected at random, what is the probability that its ones place is less than its tens palce, its tens place is less than its hundreds place, and its hunders place is less than its thousands place? (the first digit of an n-digit number is nonzero.
thanks very much!!!!
probability questions ,,help ,,thanks!!
2007-01-09 8:09 pm
回答 (2)
2007-01-09 9:10 pm
✔ 最佳答案
1. n(S)=52!
n(A)=4!(13!)^4
P(A)=4!(13!)^4/52!
2.
★
[9]→[8]→[7]→[6]→[5]→[4]→[3]→[2]→[1]→[0]
n(S)=9000
n(A)=1x7+3x6+6x5+10x4+15x3+21x2+28x1=210
P(A)=7/300
2007-01-09 13:18:41 補充：
由9去到6、由8去到5、……由3去到0，各有1個方法由9去到5、由8去到4、……由4去到0，各有3個方法由9去到4、由8去到3、……由5去到0，各有6個方法由9去到3、由8去到2、……由6去到0，各有10個方法由9去到2、由8去到1、由7去到0，各有15個方法由9去到1、由8去到0，各有21個方法由9去到0，有28個方法觀察所知，右邊的方法數為三角形數列
2007-01-09 13:20:27 補充：
第一題若把咭上的數字忽略其方法有所不同n(S)=52!/(13!)^4n(A)=4!P(A)=4!(13!)^4/52!答案亦無異矣
2007-01-09 9:04 pm
1
--------------------------------
4 (to the power of 13)
11
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900
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4 (to the power of 13)
11
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900
收錄日期: 2021-04-12 21:21:41
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https://hk.answers.yahoo.com/question/index?qid=20070109000051KK00886