作业帮一道关于概率的英文数学题7) A box contains 3 red,4 white and 5 blue discs.Three discs are selected at randomfrom the box.Find the probability that:a) all three discs are the same colour,if the selection is with replacement b) all three dis
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一道关于概率的英文数学题7) A box contains 3 red,4 white and 5 blue discs.Three discs are selected at randomfrom the box.Find the probability that:a) all three discs are the same colour,if the selection is with replacement b) all three dis
一道关于概率的英文数学题
7) A box contains 3 red,4 white and 5 blue discs.Three discs are selected at random
from the box.Find the probability that:
a) all three discs are the same colour,if the selection is with replacement
b) all three discs are of different colours,if the selection is without replacement
翻译人人都会
一道关于概率的英文数学题7) A box contains 3 red,4 white and 5 blue discs.Three discs are selected at randomfrom the box.Find the probability that:a) all three discs are the same colour,if the selection is with replacement b) all three dis
额````翻译楼上的已经做了,我就直接解答了.
a、颜色相同有3种情况,我们要分别计算
就是1/4*2/11*1/10+1/3*3/11*1/5+5/12*4/11*3/10=3/44就是这个概率啦~
b、这个跟上面挺像的,就是有点麻烦
1/4*4/11*1/2+1/4*5/11*2/5+1/3*3/11*1/2+1/3*5/11*3/10+5/12*3/11*2/5+5/12*4/11*3/10=3/11
真是累人,就是要分情况讨论,倒不是很难,就是不同顺序的搭配
a)P=(1/4)^3+(1/3)^3+(5/12)^3
b)P=C(3,1)*C(4,1)*C(5,1)/C(12,3)
7) A box contains 3 red, 4 white and 5 blue discs. 7 ）中包含3红， 4白色和蓝色光盘5 。 Three discs are selected at random三盘随意挑选的
from the box.从盒子。 Find the probability that:找到的概率：
a) all three discs are t...
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7) A box contains 3 red, 4 white and 5 blue discs. 7 ）中包含3红， 4白色和蓝色光盘5 。 Three discs are selected at random三盘随意挑选的
from the box.从盒子。 Find the probability that:找到的概率：
a) all three discs are the same colour, if the selection is with replacement a ）所有三个光盘是相同的肤色，如果选择与更换
b) all three discs are of different colours, if the selection is without replacement b ）所有三个光盘不同的颜色，如果选择不更换
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