sos！求救数学spm！

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siyu1884

2011-11-16 06:46 PM

2 3 5 6

all these four card are put into a box. A two-digit number is to be formed by using any two of the numbers. Two cards are picked random, one after another , with replacement.

(a)List the sample space.

(b)List all the outcomes of the events and find the probability that

(i)the numberformed is an even number,

(ii)the number formed is a prime number or a multiple of 3.

我不会做这题，谁可以教教我

感激不尽

Kianmin0908

2011-11-16 06:52 PM

3年前的我可能帮得到～可是3年后的今天的我忘了怎样做了~

哈利波特_书虫

2011-11-16 06:53 PM

two digit is formed --22,23,25.26,32.35.36....以此类推，那些就是sample space

MarsNg

2011-11-16 06:55 PM

本帖最后由 MarsNg 于 2011-11-16 08:06 PM 编辑

a)S={（2,3）（2,5）（2,6）（3,2）（3,5）（3,6）（5,2）（5,3）（5,6）（6,2）（6,3）（6,5）}
b)i.{(2,6)(3,2)(3,6)(5,2)(5,6)(6,2)},so,probability=6/12=1/2
ii.{(2,3)（3,6)(5,3)(6,3)},so,probability=4/12=1/3

siyu1884

2011-11-16 06:55 PM

3年前的我可能帮得到～可是3年后的今天的我忘了怎样做了~
Kianmin0908 发表于 2011-11-16 06:52 PM

那没关系吧~~~反正过了明天我也是会忘记的

jiayupeach

2011-11-16 06:56 PM

本帖最后由 jiayupeach 于 2011-11-16 06:58 PM 编辑

a) 23,25,26,
35,36,32,
53,52,56
63,62,65
b)
i) 2 x1 = 2
2/12 =1/6
ii) prime : 23, 53
multiple of 3 : 26 ,36,63
so 5
5/12

siyu1884

2011-11-16 06:57 PM