1. The problem statement, all variables and given/known data The numbers 1 to 25 are arranged in a square array of five rows and five columns in an arbitrary way. The greatest number in each row is determined, and then the least number of these five is taken; call that number s. Next, the least number in each column is determined, and then the greatest number of these five is taken; this number is called t. Prove that s is equal to or greater than t for all possible arrangements. 2. Relevant equations 3. The attempt at a solution I see intuitively that this is the case but have no idea where to start with a proof.