03 Oct '10 14:09>
A different version of a puzzle I put up some time ago.
I have 4 identical bags each containing 2 balls.
1 bag has 2 white balls
1 bag has 2 black balls
2 bags have 1 black and 1 white
I pick a bag at random and take out a ball. It is black.
What is the probability of the other ball being black?
I have 4 identical bags each containing 2 balls.
1 bag has 2 white balls
1 bag has 2 black balls
2 bags have 1 black and 1 white
I pick a bag at random and take out a ball. It is black.
What is the probability of the other ball being black?