Question 13
An exhibition centre has 25 equilateral-triangle rooms arranged as shown. Each room has a door on each of its three sides leading to a neighbouring room or outside. A visitor wants to see as many rooms as possible while passing through each room at most once. What is the maximum number of rooms the visitor can see?
Source-intended route convention: one entrance and one exit, with no leaving the building and re-entering during the visit.
Source-intended route convention: one entrance and one exit, with no leaving the building and re-entering during the visit.