IMC 2023 · Problem 6

Day 230th IMC · Blagoevgrad, Bulgaria

Statement

Ivan writes the matrix (2324)\begin{pmatrix} 2 & 3 \\ 2 & 4 \end{pmatrix} on the board. Then he performs the following operation on the matrix several times:

  • he chooses a row or a column of the matrix, and
  • he multiplies or divides the chosen row or column entry-wise by the other row or column, respectively.

Can Ivan end up with the matrix (2423)\begin{pmatrix} 2 & 4 \\ 2 & 3 \end{pmatrix} after finitely many steps?

Official solution

Hidden so you can work on the problem first.

Proposed by Alex Avdiushenko, Neapolis University Paphos, Cyprus.