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Problem of the Month – December 2024

Let S be a set consisting of 31 positive real numbers. For each non-empty subset AS let
f(A) be the product of all elements of A. We say that a subset AS is rational if f(A) is
a rational number. We say that a subset AS is irrational if f(A) is an irrational number.
Is there any set S having exactly 2023 rational subsets? Is there any set S having exactly
2025 irrational subsets?

 

Correct Solutions by,

  • Toshihiro Shimizu Kawasaki, Japan
  • Magnus Jakobsson Lund, Sweden
  • Jepbar Asgarov Aşgabat, Turkmenistan
  • Alper Balcı Ohio State University
  • Hamza Akdeniz Bilkent University
  • Mehmet Samet Ödük METU
  • Arda Karahan Trabzon Fen Lisesi

Solution: 2412a.pdf (bilkent.edu.tr)