标题: 求解一道DS题！！谢谢！ [打印本页] 作者: Seajinking 时间: 2015-9-27 15:31 标题: 求解一道DS题！！谢谢！ 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.
这种题目怎么很快做出判断？因为选的时候一直在犹豫是自己不会还是算不出。。。
P.S.能推荐一下关于概率比较好的讲解吗？本人一碰上概率就抓瞎
作者: guoyilin2015 时间: 2015-9-27 22:46
R Red
B Blue
W White
O Odd
E Even