MathDB
2012 ToT Spring Junior A p3, guard on duty for n days in a row

Source:

March 4, 2020
combinatorics

Problem Statement

In a team of guards, each is assigned a different positive integer. For any two guards, the ratio of the two numbers assigned to them is at least 3:13:1. A guard assigned the number nn is on duty for nn days in a row, off duty for nn days in a row, back on duty for nn days in a row, and so on. The guards need not start their duties on the same day. Is it possible that on any day, at least one in such a team of guards is on duty?