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 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

A.        0

B.        1/9

C.        2/9

D.       1/3

E.        1

答案是c,可是我算了半天，怎么总觉得是是d啊。

看见这种题就像看见抛硬币的题，第一时间排除（1/2）^3——跳tone了......

这题貌似P（3,3）/3^3＝6/27＝2/9