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Problem 341

Combinatorics Difficulty 2.0 Find the answer CEMC Fermat · Canada · 2002

A “double-single” number is a three-digit number made up of two identical digits followed by a different digit. For example, 553 is a double-single number. How many double-single numbers are there between 100 and 1000?

(A) $81$ (B) $18$ (C) $72$ (D) $64$ (E) $90$

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