这道题疯了，求牛牛指导

kgbht · 发表于 2010-3-18 16:22:49

Q11:

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The figure shown represents a board with 4 rows of pegs, and at the bottom of the board are 4 cells numbered 1 to 4.Whenever the ball shown passes through the opening between two adjacent pegs in the same row, it will hit the peg directly beneath the opening.The ball then has the probability 1/2 of passing through the opening immediately to the left of that peg and probability 1/2 of passing through the opening immediately to the right.What is the probability that when the ball passes through the first two pegs at the top it will end in Cell 2?

A.1/16
B.1/8
C.1/4
D.3/8
E.1/2

mikesun · 发表于 2010-3-18 16:41:17

选d cell1和4是对等的，cell2和3是对等的
所以进入cell1的概率为1/2的三次方即八分之一
进入cell2的概率则为（1-1/8×2）/2=3/8

kgbht · 发表于 2010-3-18 17:18:49

真牛牛啊！多谢你啦！！

Iljiajia · 发表于 2010-3-18 17:41:46

这题有点意思，需要对题目有很清楚的理解，楼主在哪找到的题目？

而且是不是图例是应该承金字塔状啊？而不是像这里显示的都靠左呢？？

kgbht · 发表于 2010-3-19 13:54:07

GWD数学啊，到处都有下载的啊

这道题疯了，求牛牛指导

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