2020 PUMaC Combinatorics A2 / B3
Source:
January 1, 2022
combinatorics
Problem Statement
Cary has six distinct coins in a jar. Occasionally, he takes out three of the coins and adds a dot to each of them. Determine the number of orders in which Cary can choose the coins so that, eventually, for each number , some coin has exactly dots on it.