TT GWD 1-2

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?

A.       0

B.       1/9

C.       2/9

D.      1/3

E.       1

答案是C,我觉得自己好像做过这个题但是今天怎么也想不起思路了！我查了讨论贴但是题号对不上。谢谢NN帮忙解答一下！！

谢谢！！

P(3,3)*(1/3)^3=6*(1/27)=C

坐三个不同座位1/27的概率

三个座位排序,乘以6

哦对对，忘了排序了！天，这丢3落4的！

诚挚的感谢kallyli!!!

另一种方法:

总的可能数:3x3x3=27

连坐的可能数:3x2=6

2/9