24 October 2013

# Puzzle time

You are shown two identical bowls in a room – one of them containing 25 white marbles and the other containing 25 black marbles. The marbles are identical to each other other than the aspect of color, of course.
A blindfold person will be brought in to the room and asked to choose any bowl randomly and pick any one marble randomly from that bowl. If it is turns out to be a white marble, you will get a million dollars. If it turns out to be black you get nothing.
However, before the blindfolded person is brought in, you are allowed to mix up all the marbles and place any number of white and any number of black marbles in each bowl. Needless to say, all marbles have to be in one or the other bowl.
How would you place the marbles (meaning how many of which color marbles in which bowl) to give you the maximum chance of winning the million dollars?

(Remember to send me FB message instead of posting it on the Comments section. I will acknowledge you in the comments section if you get it right)

Posted October 24, 2013 by Rajib Roy in category "Puzzles

1. By Rajib Roy (Post author) on

Jim already sent me the answer!!! One think I did not know is that his degree is in math!!!

2. By Rajib Roy (Post author) on

More correct answers coming in… Jasmine, Bijetri, Madhu, Lee and Subbu got it too

3. By Sreenivas Makala (Post author) on

Rajib Roy Sir,intuitively place one White Ball in one bowl and 24White and 25 Black in another bowl.I am getting the same answer if I take a generic case and try to maximise the conditional probability by first principles.Is this right?

4. By Rajib Roy (Post author) on