How to get out of the prison?

[Question]: A and B are jailed in two  room and throw a coin independently. Then they  give a guess, if at least one of them get the right answer, then they can get out, Do they have a strategy to get out of the prison.

[Answer]: Yes.  If we let A give the answer as it is, and B reverse the  answer, we have four situations: (A, B) = (1,0), (1,1), (0,0), (0,1) and their answer (F(B), F(A)) = (1, 1), (0,1), (1,0), (0,0), at least one will be right.

If we analyse a little, we will find no matter what happens, the expectation of right answer is just 1, what we need to do is to reduce the 0. So we need to make their prediction as two random variable correlated. This is the strategy and we make some try to get the right answer.