MathDB
2017 Guts #13: Frogs and toads

Source:

February 21, 2017
combinatorics

Problem Statement

The game of Penta is played with teams of five players each, and there are five roles the players can play. Each of the five players chooses two of five roles they wish to play. If each player chooses their roles randomly, what is the probability that each role will have exactly two players?