求助排列组合难题：prep-ds1-158

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.

搞不懂这题的思路，紧急求助！

同问。btw, i guess answer E?

应该是E

条件1 说明了 同时为白球和偶数的情况不存在 交集为0，对解题没任何帮助

条件2 说明了 两者差为0.2，但是交集存不存在不知道，各自的概率也不知道，不充分

1和2 可以推出 X-Y=0.2 但是要求X+Y，还是解不出来。

所以E