"But this is three cards. No matter how to turn, this is a third of the probability. How did he become zero?" Shirley Tommy doesn't understand.

Martin James smiled. "Shirley asked well, how can you make probability zero? Then there is only one possibility, let k disappear, let three cards become a, then, no matter how I turn, will lose no doubt. "

Morgan Gracie suddenly realized,

"So, you choose the opposite. Instead of turning K, you turn over two A's and say the one you chose is K."

"Morgan is right, if I'm not mistaken, the one I chose was actually A and all three were actually A." Martin...