AMC 8 1987 Problem 25

AMC8 1987 年第 25 题

概率★★★★☆

Ten balls numbered 1 to 10 are in a jar. Jack reaches into the jar and randomly removes one of the balls. Then Jill reaches into the jar and randomly removes a different ball. The probability that the sum of the two numbers on the balls removed is even is

一个罐子中有编号 1 到 10 的十个球。Jack 从罐中随机取出一个球。然后 Jill 从罐中随机取一个不同的球。取出的两个球上的数字之和为偶数的概率是

A. $\displaystyle \frac{4}{9}$
B. $\displaystyle \frac{9}{19}$
C. $\displaystyle \frac{1}{2}$
D. $\displaystyle \frac{10}{19}$
E. $\displaystyle \frac{5}{9}$

正确答案 · Correct Answer

A

解析 · Solution

解析整理中

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