19th Eötvös Competition Problems 1912

1.  How many n-digit decimal integers have all digits 1, 2 or 3. How many also contain each of 1, 2, 3 at least once? 2.  Prove that 5n + 2 3n-1 + 1 = 0 (mod 8). 3.  ABCD is a quadrilateral with vertices in

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