2#
大 中
小 發表於 2011-5-9 06:32 PM (第 4754 天)
顯示全部帖子
[顯示]
[隱藏]
P(R)=(7/12)[(6/10)(7/12)+(4/10)(6/12)]+(5/12)[(5/10)(8/12)+(4/10)(7/12)+(1/10)(7/12)]
=93/160
P(B)=(7/12)(6/10+4/10)(5/12)+(5/12)[(5/10+4/10)(4/12)+(1/10)(5/12)]
=37/96
P(G)=1-P(R)-P(B)=1/30
To Solve these Problem,Tree diagram is a GREAT Technique.
Count the ball in each bag in each case and write down once,
then you can operate "+" or "x" to solve all answer you want.
[ 本帖最後由 hinokari 於 2011-5-9 06:33 PM 編輯 ]