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MathNet 2018-part-02 — 181 problems (EN–VI) Question 163

Math Olympiad Vault · MathNet 2018-part-02 — 181 problems (EN–VI)

Question 163

The integers from $1$ to $9$ are placed in the cells of a $3 \times 3$ grid. For $i=1$, $2$ and $3$, let $\ell_{i}$ denote the largest integer in the $i^{\text{th}}$ row and $c_{i}$ the smallest integer in the $i^{\text{th}}$ column.

How many grids are there such that $\min \left\{\ell_{1}, \ell_{2}, \ell_{3}\right\}=\max \left\{c_{1}, c_{2}, c_{3}\right\}=4$?