求助一道概率题

cheekar

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

B.        1/9

C.        2/9

D.       1/3

E.        1

Answer: c可我不知道怎么算出来的？

tinajanuary

 一共选3个，第一个随便拿，第二个从剩下的两个里面拿即2/3，第三个拿最后一个没被拿的1/3   所以是2/3*1/3