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标题: 数学求助- GWD15 29 [打印本页]

作者: saffsa761    时间: 2013-2-28 07:22     标题: 数学求助- GWD15 29

A certain roller coaster has 3 cars, and a passenger is equally likely to ride in any 1 of the 3 cars each time that passenger rides the coller coaster. If a certain passenger is to ride the roller coaster 3 times, what is probability that the passenger will ride in each of the 3 cars?

Answer: 2/9
求解过程,谢谢!
作者: liliannechang    时间: 2013-2-28 19:27

正规排列组合的说法我也忘了怎么说- -
不过你可以这样想:要满足3次坐不同的车,第一次做哪个都一样,概率是1.第二次要坐剩下两个,概率是2/3.最后一次么,显然是1/3. 乘起来。
作者: saffsa761    时间: 2013-3-1 06:44

谢谢! 我原来把第一次选择用1/3 来乘了。




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