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, 2020

Number theory Difficulty 3.0 AMC 10/12 Find the answer United Kingdom

Masha put a multiplication sign between the second and third digits of the number 20202020 and noted that the resulting product 20×2020 \times 20 was a square number. How many integers between 20102010 and 20992099 (including 20202020) have the same property?

(A) 11 (B) 22 (C) 33 (D) 44 (E) 55

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