Then P(A 3 )=,
(ii) let "winning in a competition" be event B, then B=A 2 ∪A 3,
P(A 2 )=, A 2 and A 3 are mutually exclusive,
So p (b) = p (A2)+p (A3) =;
According to the meaning of the question, all possible values of x are 0, 1, 2.
P(X=0)=( 1﹣ ) 2 =,
p(x = 1)= c 2 1( 1﹣)=,
P(X=2)=( ) 2 =,
So the distribution list of x is
Mathematical expectation of x e (x) = 0.