Author Topic: IBM 五月  (Read 4311 times)


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IBM 五月
« on: 六月 13, 2014, 01:40:17 pm »
以前FZY 常在这里贴IBM 每月的问题。好久没有人贴了。今天有人问我这个问题,觉得很有趣,再贴一次。答案已经出来了。但没有证明。看大家有没有好的证明。

Every second, a gun shoots a bullet in the same direction at a random constant speed between 0 and 1.

The speeds of the bullets are independent uniform random variables. Each bullet keeps the exact same speed and when two bullets collide, they are both annihilated.

After shooting 20 bullets, what is the probability that eventually all the bullets will be annihilated?