Question 854714
Not quite. For example, suppose A and B only occur together, that is, B is true if and only if A is true, and suppose P(A) = 1/2. Then P(B) = 1/2, so P(A and B) = 1/2 but P(A) + P(B) = 1.


The last condition must be true -- if P(B|A) = P(B), then A and B are independent.