f5 math
2009-10-07 4:42 am
ann has 7 gold coins and 3silver coins .bob has 4gold cons and 8silver coins.if they exchange one of their coins at rando find the probability that the respective number of gold coins and silver coins with each of them remains the same
回答 (1)
2009-10-07 4:48 am
✔ 最佳答案
P(the respective number of gold coins and silver coins with each of them remains the same )= P(they exchange two gold coins) + P(they exchange two silver coins)
= 7/(7+3) * 4(4+8) + 3/(7+3) * 8/(4+8)
= (7/10)(4/12) + (3/10)(8/12)
= 7/30 + 1/5
= 13/30
2009-10-06 21:22:59 補充：
7/(7+3) * 4(4+8) + 3/(7+3) * 8/(4+8)
should be
7/(7+3) * 4/(4+8) + 3/(7+3) * 8/(4+8)
收錄日期: 2021-04-21 22:05:02
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20091006000051KK01339