题目内容
(2013•郴州模拟)小明和小红是明星学校八年级的同学,期末考试八年级共安排10个考室,电脑随机分配,请问小明和小红被安排在同一考室的概率是
.
1 |
10 |
1 |
10 |
分析:列表得出所有等可能的情况数,找出两人安排在同一考室的情况数,即可求出所求的概率.
解答:解:列表如下:
所有等可能的情况有100种,其中小明与小红被安排在同一考室的情况有10种,
则P=
=
.
故答案为:
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | |
1 | (1,1) | (2,1) | (3,1) | (4,1) | (5,1) | (6,1) | (7,1) | (8,1) | (9,1) | (10,1) |
2 | (1,2) | (2,2) | (3,2) | (4,2) | (5,2) | (6,2) | (7,2) | (8,2) | (9,2) | (10,2) |
3 | (1,3) | (2,3) | (3,3) | (4,3) | (5,3) | (6,3) | (7,3) | (8,3) | (9,3) | (10,3) |
4 | (1,4) | (2,4) | (3,4) | (4,4) | (5,4) | (6,4) | (7,4) | (8,4) | (9,4) | (10,4) |
5 | (1,5) | (2,5) | (3,5) | (4,5) | (5,5) | (6,5) | (7,5) | (8,5) | (9,5) | (10,5) |
6 | (1,6) | (2,6) | (3,6) | (4,6) | (5,6) | (6,6) | (7,6) | (8,6) | (9,6) | (10,6) |
7 | (1,7) | (2,7) | (3,7) | (4,7) | (5,7) | (6,7) | (7,7) | (8,7) | (9,7) | (10,7) |
8 | (1,8) | (2,8) | (3,8) | (4,8) | (5,8) | (6,8) | (7,8) | (8,8) | (9,8) | (10,8) |
9 | (1,9) | (2,9) | (3,9) | (4,9) | (5,9) | (6,9) | (7,9) | (8,9) | (9,9) | (10,9) |
10 | (1,10) | (2,10) | (3,10) | (4,10) | (5,10) | (6,10) | (7,10) | (8,10) | (9,10) | (10,10) |
则P=
10 |
100 |
1 |
10 |
故答案为:
1 |
10 |
点评:此题考查了列表法与树状图法,用到的知识点为:概率=所求情况数与总情况数之比.
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