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Problem of the Month – November 2025

Let P1, . . . , P1024 be distinct points marked on a circle, and let a1, a2, . . . , a1024 be distinct real numbers written on these points, respectively. For each point Q on this circle different than P1, . . . , P1024, we say that Pi is Q-good if ai is the greatest number on at least one of the two arcs PiQ on this circle. Let the score of Q be the number of Q−good points on the circle. Determine the greatest integer k such that regardless of the values of a1, a2, . . . , a1024, there exists a point Q with score at least k.

 

 

Correct Solutions by,

  • Toshihiro Shimizu Kawasaki, Japan
  • Mehmet Sarak Bilkent University
  • Yunus Orazow 40th Specialized School, Ashkabat, Turkmenistan
  • Emir Kara Gazi Anadolu Lisesi, Ankara
  • Mustafa Kaynak Gaziantep
  • Erenalp Yuca Bilkent University
  • Abdulkadir Tanrıverdi Eskişehir
  • Magnus Jakobsson Lund, Sweden
  • Roger Bengtsson Lund, Sweden
  • Alper Balcı Ohio State University, USA
  • Özgür Soysal Bilkent University
  • Ananda Raidu Rajahmundry, India

Solution: https://math.bilkent.edu.tr/Problem/2511a.pdf