Two persons `A` and `B` get together once a weak to play a game. They always play `4` games . From past experience Mr. A wins `2` of the `4` games just as often as he wins `3` of the `4` games. If Mr. A does not always wins or always loose, then the probability that Mr. A wins any one game is (Given the probability of A's wining a game is a non-zero constant less than one).