请教GWD数学1-2

missing_90

希望谁能帮帮我，谢谢了！

A certain roller coaster has 3 cars, and a passenger is equally likely to rid in any 1 of the 3 cars each time that passenger rides the roller coaster. If a certain passenger is to ride the roller coaster 3 times, what is the probability that the passenger will ride in each of the 3 cars?
a. 0
b. 1/9
c. 2/9
d. 1/3
e. 1

answer: c
my choice: b

yujingmm

题目：某过山车三节车厢，某人坐三次，其正好每个车厢坐一次的概率是多少

1）这个人做三次，一共有多少种坐法

3×3×3=27种（每次选择，他可以选3车厢的一个，一共选三次）

2）每个车厢都坐一次，有多少种坐法

P(3,3)=3×2×1=6种（3个不同车厢，按照第几次坐，排序）

所以6/27=2/9

missing_90

不胜感激！！