On an intriguing urn probability problem
Abstract
We discuss an urn probability problem, which has recently appeared on social media as a puzzle, whose analysis necessitates a prior opinion on the urn contents, and has much pedagogical merit. The derived calculations are intuitively challenging and vary to a significant extent as a function of the given prior distribution. Finally, we contrast solutions for sampling with and without replacement settings, revealing a paradoxical situation with independent draws achieved without replacement and dependent draws achieved with replacement.
Fields of Study & Subjects
Probability and Statistical Research
Statistics Education and Methodologies
Statistical Distribution Estimation and Applications
Publication details
- Journal / source
- The Mathematical Gazette
- Pages
- 1–6
- Publication date
- 19 January 2026
- Language
- EN