求解一道GWD数学概率题，谢谢

forman

12

[此贴子已经被作者于2009/8/16 12:52:39编辑过]

forman

对不起，编辑时出现了错误
On Saturday morning, Malachi will begin a camping vacation and he will return home at the end of the first day on which it rains.  If on the first three days of the vacation the probability of rain on each day is 0.2, what is the probability that Malachi will return home at the end of the day on the following Monday?

A.    0.008
B.    0.128
C.    0.488
D.    0.512
E.    0.640

suzy2728

以下是引用forman在2009/8/16 8:11:00的发言：
对不起，编辑时出现了错误
On Saturday morning, Malachi will begin a camping vacation and he will return home at the end of the first day on which it rains.  If on the first three days of the vacation the probability of rain on each day is 0.2, what is the probability that Malachi will return home at the end of the day on the following Monday?

A.    0.008
B.    0.128
C.    0.488
D.    0.512
E.    0.640

what about the answer? i choose B.

amjustin

这个题应该这样解答:

应该是,周六没下雨,所以概率是1-0.2=0.8,周日没下雨,概率同样也是0.8,周一下雨了应该是0.2.所以这件事情用乘法原则就是,0.8*0.8*0.2=0.128

仰莎修女

B

forman

谢谢大家的解答，答案是B