math probability question!!

2010-05-29 8:24 pm
a bag contains 5 chocolate, 3 peanut butter, 4 oatmeal, and 4 sugar cookie.
if 2 cookies are selected randomly, what is the probability that they will be the
same kind.

回答 (1)

2010-05-29 10:02 pm
✔ 最佳答案
Total number of cookies = 5 + 3 + 4 + 4 = 16

P(2 chocolate) = 5/16 X 4/15 = 1/12

P(2 peanut butter) = 3/16 X 2/15 = 1/40

P(2 oatmeal) = 4/16 X 3/15 = 1/20

P(2 sugar) = 4/16 X 3/15 = 1/20

As the above events are all mutually exclusive, so the required probability

= P(2 of the same kind)

= 1/12 + 1/40 + 1/20 + 1/20

= 5/24
參考: Prof. Physics


收錄日期: 2021-04-19 22:21:26
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100529000051KK00549

檢視 Wayback Machine 備份