扫描二维码，直接登录
题库 / Prep2007E1-DS-158
Each of the 25 balls in a certain box is either red, blue, or white and has a number from 1 to 10 painted on it. If one ball is to be selected at random from the box, what is the probability that the ball selected will either be white or have an even number painted on it?
(1) The probability that the ball will both be white and have an even number painted on it is 0.
(2) The probability that the ball will be white minus the probability that the ball will have an even number painted on it is 0.2.
Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
EACH statement ALONE is sufficient.
Statements (1) and (2) TOGETHER are NOT sufficient.
问题是，P（B）偶数的概率不是应该可以通过题目算出来吗？
我是这么思考的，25个球，1-10，然后1-10，最后1-5，偶数球的概率可以算出来的，为啥算不出来呢？
难道是1-10是随机喷的？
登录 或 注册 后可以参加讨论