x******u
发帖数: 259 | 1 Mike, Ben and Sam are playing a dice game. Mike goes first, Ben second and
Sam third. The first person to roll a three wins and the game is over. The
dice are continuously passed in the above order until someone wins. What is
the probablility that Sam wins? |
h***o
发帖数: 2321 | 2 25/91
is
【在 x******u 的大作中提到】
: Mike, Ben and Sam are playing a dice game. Mike goes first, Ben second and
: Sam third. The first person to roll a three wins and the game is over. The
: dice are continuously passed in the above order until someone wins. What is
: the probablility that Sam wins?
|
x******u
发帖数: 259 | 3 牛.能展开说说怎么做的呀.
【在 h***o 的大作中提到】
: 25/91
:
: is
|
I*M
发帖数: 1533 | 4 1. Sam wins in the first round:prob(Sam wins)=(5/6）*（5/6）*（1/6）=P
２． if all of them lose in the first round, prob(all lose)=(5/6)^3=x
Sam wins in the second round:P*x
3. sam wins in the third round: P*(x^2)
....
add up all probs=25/91
【在 x******u 的大作中提到】
: 牛.能展开说说怎么做的呀.
|
h**k
发帖数: 3368 | 5 25/(25+30+36)=25/91
【在 x******u 的大作中提到】
: 牛.能展开说说怎么做的呀.
|
