Maths Olympiad Prep

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, 2025

Algebra Difficulty 1.4 Junior Find the answer Canada

A list of one-digit integers contains exactly one 11, two 22s, three 33s, four 44s, five 55s, and six 66s. What is the median of this list?

Pick one

Solution

Ordered from smallest to largest, the list is 1,2,2,3,3,3,4,4,4,4,5,5,5,5,5,6,6,6,6,6,61,2,2,3,3,3,4,4,4,4,5,5,5,5,5,6,6,6,6,6,6
This list contains 1+2+3+4+5+6=211+2+3+4+5+6=21
integers.

The median is the middle number in an ascending (or descending) list of
numbers.

The 11th integer in the list of 2121
integers above has 1010 integers
before it and 1010 integers following
it, and thus is the median of the list.

The 11th integer and the median of the given list is 55.

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Source: CEMC, University of Waterloo, licensed CC-BY-NC-4.0. Statement reproduced verbatim; metadata (topic, difficulty) added by this project.