GWD 第一套 第二题求解

luyi1988

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?

0
1/9
2/9
1/3
1

标准答案是C    我决的答案应该是1/27

hukeab

乘客在选第一辆车时候有三种选择，选第二辆车的时候，为了不重复，需要除去前面的已选择的车，所以有两种选择，最后第三辆车有一种选择，故3*2*1=6，一共是3*3*3，所以概率为2/9

luyi1988

非常感谢