請問GWD1-2

[stellaadixen]

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


請問這題該如何解?

[eiswein]

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


請問這題該如何解?

1*2/3*1/3=2/9
答案C

[stellaadixen]

請問可以解釋一下嗎？

[eiswein]

三個車廂分別叫做A,B,C
今天有個乘客要去坐三次，要求每個車廂分別乘坐到一次的機率為何？

第一次乘客去的時候，他可以隨意挑選車廂(3/3)，第二次的時候先前乘坐過的那個車廂不能坐了(2/3)，必須從剩下兩個車廂中挑一個，最後一次去的時候，只剩那個還沒做過的車廂可以選擇了(1/3)。

1*2/3*1/3=2/9

這樣看的懂嘛..

[stellaadixen]

謝謝您.真是太感激了