Caja de predicción de moneda

Magicians have a little money box, can put one yuan or fifty cents coin, to the audience by a one yuan and fifty cents coin, and then the magician turned the audience according to their preferences will put a coin into the box tightly put on the table, and the other hide a coin, the magician does not touch the box in the case, according to telepathy can guess the audience go into a dollar or fifty cents. Very magical magic money box.