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: .