MathDB
elevetors 1-8

Source: Portugal OPM 2017 p6

May 15, 2024
combinatorics

Problem Statement

In a building whose floors are numbered 11 to 88, the builder wants to place elevators so that, for every choice of two floors, there are always at least three elevators that stop on those floors. Furthermore, each elevator can only stop at a maximum of 55 floors. What is the minimum number of elevators that need to be placed?