NO.PZ2019040801000007
问题如下：
600 table tennis balls are placed in a black box, three of which are written with different words. On a random draw, what is the probability that one of these 3 balls will be drawn?
选项：
A.0.004.
B.0.005.
C.0.010.
D.0.008.
解释：
B is correct.
考点：Basic probability calculation
解析：P(ball1 or ball 2 or ball 3) = 1/600 + 1/600 + 1/600 = 3/600 = 0.005
根据加法法则，P(A or B or C)=P(A or B)+P(C)-P(A or B * C)=P(A)+P(B)-P(AB)+P(C)-P(A or B * C) 对吗？
P(A or B or C)为什么等于1/600+1/600+1/600
