# Banach's matchbox problem

> problem in probability: Banach has 2 matchboxes (initially with 𝑁 matches) in left and right pockets; if he reaches into his pocket and finds for the 1st time that the box picked is empty, what’s the probability that there are 𝑘 matches in the other?

**Wikidata**: [Q4352773](https://www.wikidata.org/wiki/Q4352773)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Banach's_matchbox_problem)  
**Source**: https://4ort.xyz/entity/banach-s-matchbox-problem