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MathNet 2018-part-07 — 177 problems (EN–VI) Question 175

Math Olympiad Vault · MathNet 2018-part-07 — 177 problems (EN–VI)

Question 175

The Crocodile thought of four unit squares of a $2018 \times 2018$ forming a rectangle with sides $1$ and $4$. The Bear can choose any square formed by $9$ unit squares and ask whether it contains at least one of the four Crocodile's squares. What minimum number of questions should he ask to be sure of at least one affirmative answer?