Probability question


3 boxes practically indistiguishable in appearance have 2 drawers 1 contains a gold coin in first silver coin in the other drawer , box2 contains a gold coin in each drawer and box3 contains a silver coin in each box is chosen at random and one of its drawers is copied at random and a gold coin is found.what is the probability that the other drawer contains a coin of silver


Let C1C1 = event that cabinet 1 is chosen

Let C2C2 = event that cabinet 2 is chosen

Let SS = event that a silver coin is chosen