求问一道GWD上的数学题，觉得应该选B，但答案是C

慕沙Hunter

Q2:
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?这句话的意思是说这个乘客每次乘的是不一样的车的概率是多少，对吗？


A.0
B.1/9
C.2/9
D.1/3
E.1

慕沙Hunter

谢谢啊~今天做GWD2的时候又出现了，自己也忽然明白了~~

h14zpsn

答案是C，假设车厢是A,B,C, 一个人去做三次那么就有27种可能性3*3*3，如果按照顺序不重复做，第一次做了A车厢，那么接下来两次做BC,或者CB，同理可证，这样子的可能性有2+2+2=6，所以6/27=2/9，所以为C