L1
Bertrand's Box Paradox
Junior Quant · Brainteasers & Logic
Box 1
Box 2
Box 3
Pick a box at random, draw one coin — it is gold. What is the probability the other coin is also gold?
Question
You have 3 boxes: one with two gold coins, one with two silver coins, one with one of each. You pick a box at random and draw a coin — it's gold. What is the probability the other coin is also gold? Use Bayes' theorem, not intuition.