则P(A)=
2 |
5 |
3 |
4 |
1 |
3 |
设X表示合格人数,则X=0,1,2,3,
P(X=0)=(1-
2 |
5 |
3 |
4 |
1 |
3 |
1 |
10 |
P(X=1)=
2 |
5 |
3 |
4 |
1 |
3 |
2 |
5 |
3 |
4 |
1 |
3 |
2 |
5 |
3 |
4 |
1 |
3 |
25 |
60 |
P(X=2)=(1-
2 |
5 |
3 |
4 |
1 |
3 |
2 |
5 |
3 |
4 |
1 |
3 |
2 |
5 |
3 |
4 |
1 |
3 |
23 |
60 |
P(X=3)=
2 |
5 |
3 |
4 |
1 |
3 |
1 |
10 |
∴最容易出现1人合格的情况.
2 |
5 |
3 |
4 |
1 |
3 |
2 |
5 |
3 |
4 |
1 |
3 |
2 |
5 |
3 |
4 |
1 |
3 |
1 |
10 |
2 |
5 |
3 |
4 |
1 |
3 |
2 |
5 |
3 |
4 |
1 |
3 |
2 |
5 |
3 |
4 |
1 |
3 |
25 |
60 |
2 |
5 |
3 |
4 |
1 |
3 |
2 |
5 |
3 |
4 |
1 |
3 |
2 |
5 |
3 |
4 |
1 |
3 |
23 |
60 |
2 |
5 |
3 |
4 |
1 |
3 |
1 |
10 |