柱 V=Sh、锥 V=3Sh、球 V=34πR3——体积公式是重点。
How many people do we need to have in a room to make it a favorable bet (probability of success greater than 1/2) tha…
一个教室里随便点 23 个人,两两生日撞上的概率刚过半。直觉猜 183,真答案是 23。