问题如下图：
选项：
A. 
B. 
C. 
解释：
为什么不是0.20*0.10=0.02？ 不明白答案里为什么这么计算
NO.PZ2015120604000073 问题如下 Accorng to the above table, whiof the following statements is the most correct? A.If performanof toy's bonmarket is poor, the contionprobability of having gooperformanof next y's bonmarket is equto 0.01. B.If performanof toy's bonmarket is poor, the contionprobability of having gooperformanof next y's bonmarket is equto 0.20. C.If performanof toy's bonmarket is poor, the contionprobability of having gooperformanof next y's bonmarket is equto 0.50. B is correct.P(gooperformanof next y/poor performanof toy)=0.2, whiis shown in the table. 04*0.2除以（0.4*0.2+0.4*0.5+0.4*0.3）
NO.PZ2015120604000073 问题如下 Accorng to the above table, whiof the following statements is the most correct? A.If performanof toy's bonmarket is poor, the contionprobability of having gooperformanof next y's bonmarket is equto 0.01. B.If performanof toy's bonmarket is poor, the contionprobability of having gooperformanof next y's bonmarket is equto 0.20. C.If performanof toy's bonmarket is poor, the contionprobability of having gooperformanof next y's bonmarket is equto 0.50. B is correct.P(gooperformanof next y/poor performanof toy)=0.2, whiis shown in the table. 这道题不是说在一个事件发生的前提下，这个事件发生吗？不应该用P(B|A)=P(AB)/P(A)这个公式吗？就是0.2/0.4
NO.PZ2015120604000073 问题如下 Accorng to the above table, whiof the following statements is the most correct? A.If performanof toy's bonmarket is poor, the contionprobability of having gooperformanof next y's bonmarket is equto 0.01. B.If performanof toy's bonmarket is poor, the contionprobability of having gooperformanof next y's bonmarket is equto 0.20. C.If performanof toy's bonmarket is poor, the contionprobability of having gooperformanof next y's bonmarket is equto 0.50. B is correct.P(gooperformanof next y/poor performanof toy)=0.2, whiis shown in the table. （1）请问老师，这段题目如何判断出表达的是条件概率，而不是二叉树（需要相乘）~（2）如果题目答案为相乘形式，即第一天市场poor的概率乘以第二天市场goo概率，请问题干一般如何表达？谢谢老师。
老师可以写一下具体计算过程吗？
不应该是0.4*0.2吗？
