probability question
2012-08-05 4:18 am
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please help me to calculate question 15b only.
answer:293/3270
回答 (1)
2012-08-05 6:04 am
✔ 最佳答案
a)150 + 180 + 925 - 1200 = 55 students join both.b) P(At least 1 of them join both)
= 1 - P(All of them not join both)
= 1 - P(The 1st student not join both) * P(The 2nd student not join both)
= 1 - (1200 - 55)/1200 * (1200 -55 -1)/1199
= 1 - 229/240 * 104/109
= 1 - 229/109 * 13/30
= 1 - 2977/3270
= 293 / 3270
收錄日期: 2021-04-21 22:30:21
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20120804000051KK00733