How can 20 balls, 10 white and 10 black, be put into two urns so as to maximize the probability of drawing a white ball if an urn is selected at random and a ball is drawn at random from it?
Hello, novas51791!
This is a classic (very old) puzzle.
How can 20 balls, 10 white and 10 black, be put into two urns
so as to maximize the probability of drawing a white ball
if an urn is selected at random and a ball is drawn at random from it?
Solution: .
We have: .
. .
. . Hence: .
. .
. . Hence: .
Therefore: .