An urn initially contains 5 white and 7 black balls. Each time a ball is selected, its color is noted and it is replaced in the urn along with 2 other balls of the same color. Compute the probability that a. the first 2 balls selected are black and the next 2 are white; b. of the first 4 balls selected, exactly 2 are black.
时间: 2023-02-18 19:58:29 浏览: 55
a. 首先抽出2个黑球和2个白球的概率为:7/12 * 6/13 * 5/15 * 4/17 = 0.096。
b. 首先抽出2个黑球和2个白球的概率为:7/12 * 6/13 * 5/15 * 4/17 = 0.096。
相关问题
Show the result of inserting 10, 12, 1, 14, 6, 5, 8, 15, 3, 9, 7, 4, 11, 13, and 2, one at a time, into an initially empty binary heap.
插入10后,堆为:10
插入12后,堆为: 12
/
10
插入1后,堆为: 12
/ \
10 1
插入14后,堆为: 14
/ \
10 12
***堆为: 14
/ \
10 12
/ \ / \
1 6 5 8
/
10
插入5后,堆为: 14
/ \
10 12
/ \ / \
1 6 5 8
/ \
10 5
插入8后,堆为: 14
/ \
10 12
/ \ / \
1 6 5 8
/ \
10 5
/
8
插入15后,堆为: 15
/ \
10 14
/ \ / \
1 6 5 8 12
插入3后,堆为: 15
/ \
10 14
/ \ / \
1 6 5 8 12
/ \
3 10
/ \
8 5
插入9后,堆为: 15
/ \
10 14
/ \ / \
1 6 5 8 12
/ \
3 10
/ \ \
8 5 9
插入7后,堆为: 15
/ \
10 14
/ \ / \
1 6 5 8 12
/ \ /
7 10 9
/ \ /
8 5 3
插入4后,堆为: 15
/ \
10 14
/ \ / \
1 6 5 8 12
/ \ / \
7 10 9 4
/ \ /
8 5 3
插入11后,堆为: 15
/ \
10 14
/ \ / \
1 6 5 8 12
/ \ / \
7 11 9 4
/ \ /
8 5 3
插入13后,堆为: 15
/ \
10 14
/ \ / \
1 6 5 8 12
/ \ / \
7 11 9 4
/ \ / \
8 5 3 13
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```javascript
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