Maths Olympiad Prep

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Combinatorics Difficulty 3.0 AMC 10/12 Find the answer United Kingdom

Alison has a set of ten fridge magnets showing the integers from 00 to 99 inclusive. In how many different ways can she split the set into five pairs so that the sum of each pair is a multiple of 55?

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

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