Sunday, 17 January 2016

strategy - How to survive, with statistics


You are kidnapped and your offender plays a game with you. In front of you are 2 boxes, containing a total of 50 white balls and 50 black balls. The kidnapper will pull out a ball from one of the two boxes, at random. If the ball is white you survive, if not, you are shot.





  • Every ball must be in one of the boxes.

  • No balls can be left out.

  • Each box must have at least one ball.



Box 1: 25 black balls and 25 white balls Box 2: 25 black balls and 25 white balls.


In this example the chance to live is obviously $50 \% $. How can you distribute the balls so as to increase that chance?



Answer



Box 1: 50 black balls, 49 white balls Box 2: 0 black balls, 1 white ball.
In this example the chance to live is obviously $50\%+50\%*49/99 \approx 75\%$. There is no way to increase that chance.



No comments:

Post a Comment

Understanding Stagnation point in pitot fluid

What is stagnation point in fluid mechanics. At the open end of the pitot tube the velocity of the fluid becomes zero.But that should result...