probability?
2016-10-26 3:44 pm
a bag contains 3 red buttons , 2 green buttons and 3 blue buttons. Helen repeats drawing one button at a time randomly from the bag without replacement until a blue button is drawn. Find the probability that she will make at least 3 draws.
回答 (2)
2016-10-27 8:53 am
✔ 最佳答案
P(at least 3 draws)= P(the first 2 draws are not blue)
= (5/8)(4/7)
= 5/14
2016-11-14 11:51 pm
25/31
收錄日期: 2021-04-12 00:09:43
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20161026074409AA4zl4b