题目
6.已知事件A、B满足:P(AB)=P(overline(AB)),且P(A)=p,则P(B)=____
6.已知事件A、B满足:P(AB)=P($\overline{AB}$),且P(A)=p,则P(B)=____
题目解答
答案
由已知条件 $P(AB) = P(\overline{AB})$,利用补集概率性质得:
\[ P(\overline{AB}) = 1 - P(A \cup B) \]
代入条件得:
\[ P(AB) = 1 - P(A \cup B) \]
应用概率加法公式:
\[ P(A \cup B) = P(A) + P(B) - P(AB) \]
代入上式并化简:
\[ P(AB) = 1 - [P(A) + P(B) - P(AB)] \]
\[ 0 = 1 - P(A) - P(B) \]
\[ P(B) = 1 - P(A) \]
已知 $P(A) = p$,故:
\[ P(B) = 1 - p \]
答案:$\boxed{1-p}$