Noah has on his ark 4 large coffins in which to place 8 animals
Source: 2001 Moldova JBMO TST p7
February 20, 2021
combinatorics
Problem Statement
Noah has on his ark large coffins in which to place animals.
It is known that for any animal there are at most animals with which it is incompatible (those can't live together). Show that:
a) Noah can place the animals in the cages according to their compatibility.
b) Noah can place two animals in each cage.