Ball Paradox
Discrete Mathematics
Level
2
A box initially contains a ball, which has a 50:50 chance of being black or white.
Then you put a white ball into the box, and randomly pick one ball out, which turns out to be a white ball.
What is the probability that the initial ball was white?
Note: This problem was stated by the famous author, Lewis Carroll (Charles Dodgson).
by
Worranat Pakornrat