在一个不透明的口袋里,装有红黄白三种颜色的乒乓球,其中白球2个,黄1,若从中任意摸出一个球,这个球是白球的概率为0.5,求口袋中红球的个数
人气：338 ℃ 时间：2020-01-28 08:53:48
解答
2/0.5=4 ,计算得球的总数,在用4-1-2=1,所以得1个红球.
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