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NZMOC Camp Selection Problems
2016 NZMOC Camp Selection Problems
2
2
Part of
2016 NZMOC Camp Selection Problems
Problems
(1)
real numbers in a 5x5 table
Source: New Zealand NZMOC Camp Selection Problems 2016 p2
9/19/2021
We consider
5
×
5
5 \times 5
5
×
5
tables containing a real number in each of the
25
25
25
cells. The same number may occur in different cells, but no row or column contains five equal numbers. Such a table is balanced if the number in the middle cell of every row and column is the average of the numbers in that row or column. A cell is called small if the number in that cell is strictly smaller than the number in the cell in the very middle of the table. What is the least number of small cells that a balanced table can have?
combinatorics