有红、黄、黑、白四色球各一个，放置在一个编号为1、2、3、4的四个盒子中，每个盒子放置一只球，它们的顺序不知。甲、乙、丙三人猜测放置顺序如下：甲：黑球在1号盒子，黄球在2号盒子；乙：黑球在2号盒子，白球在3号盒子；丙：红球在2号盒子，白球在4号盒子。 结果证明甲、乙、丙三人各猜中了一半，给出四色球放置在盒中的情况。-There are red, yellow, black, white each a four color ball, placed in a numbered 1, 2, 3, 4 four boxes, each box placed a ball, I do not know their order. A, b, c three speculation to place order as follows: a: black ball in the box, 1 yellow ball in the box　2, B: black ball in the box, 2 white balls in the box　3, C: the red ball in the box, 2 white balls in the box 4. Results show that a, b, c three people guessed the half, each given four color ball placed in the box.