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UKMT Senior Mathematical Challenge, 2019

Algebra Difficulty 2.0 Junior Find the answer United Kingdom

Anish has a number of small congruent square tiles to use in a mosaic. When he forms the tiles into a square of side $n$ , he has $64$ tiles left over. When he tries to form the tiles into a square of side $n+1$ , he has $25$ too few. How many tiles does Anish have?

(A) $89$ (B) $1935$ (C) $1980$ (D) $2000$ (E) $2019$

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