1.
The prpbability that Ben's father gets a job promotion is 0.8.The probability that Ben's father gets a promotion and he takes Ben to the Ocean Park is 0.72.It is known that Ben's father has been promoted.What is the probability that he takes Ben to the Ocean Park?
2.
A family has two children.It is given that the childen are not all boys.Find the probability that the family has two daughters.
probability
2011-04-26 9:56 pm
回答 (3)
2011-04-26 10:16 pm
✔ 最佳答案
For Q.1Given the 0.72 is the result of joint probability of the 2 events as mentioned in question. Now Ben's father has been promote. Thus, the probability of Ben's father to take him to Ocean Park should be:
= 0.72 / 0.8 x 1
= 0.9
====
For Q.2
Given children are not all boys, there are 2 probailities as follows:
1. All 2 are daughters
2. 1 daughter and 1 boy
In view of the above, there are 2 equal chances for each of above events
i.e. 1 / 2
= 0.5
===
2011-04-29 9:54 pm
Thanks for your explaination
2011-04-27 3:40 pm
２）
There are four probability:
BG
GB
GG
BB(rej.)
So there are three probability:
BG
GB
GG
There are one case is GG,so P(two daughters)=1/3
There are four probability:
BG
GB
GG
BB(rej.)
So there are three probability:
BG
GB
GG
There are one case is GG,so P(two daughters)=1/3
收錄日期: 2021-04-24 10:31:41
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20110426000051KK00616