F.5 math-probability(1)
2011-02-27 8:04 pm
圖片參考：http://imgcld.yimg.com/8/n/HA00265776/o/701102270040713873384980.jpg
The figure shows two roads AXYB and AZB. X, Y and Z are spots of traffic congestion and their probabilities of congestion are 0.2, 0.4 and 0.6 respectively.
(a) What is the probability of having congestion at road AXYB?
(b) If a driver chooses one of the roads at random, what is the probability of having congestion at the road chosen?
*唔該詳解
回答 (1)
2011-02-27 8:17 pm
✔ 最佳答案
(a) The probability of no congestion at road AXYB= (1 - 0.2)(1 - 0.4)
= 0.48
So, the probability of having congestion at road AXYB
= 1 - 0.48
= 0.52
(b) The driver chooses AXYB or AZB by random (with probability 1/2).
The probability of having congestion at the road chosen
= (1/2)(0.52) + (1/2)(0.4)
= 0.27 + 0.2
= 0.47
2011-02-27 12:18:02 補充：
Sorry, The probability of having congestion at the road chosen
= (1/2)(0.52) + (1/2)(0.6)
= 0.27 + 0.3
= 0.57
收錄日期: 2021-04-13 17:50:56
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20110227000051KK00407