UC知道一道关于概率的英文数学题
来源：百度知道 编辑：UC知道 时间：2024/06/20 16:59:10
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 需要解答
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 需要解答
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
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
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)