Maths Olympiad Prep

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, 2025

Combinatorics Difficulty 1.4 Junior Find the answer Canada

The words "P U G  F O R  S A L E" are written on a store window. How many of these ten letters look the
same when viewed from both sides of the window?

Pick one

Solution

When viewed from the opposite side of the window, text appears
reflected horizontally.

That is, P U G  F O R  S A L E appears
as . The letters that look the same when viewed from both sides of the
window are A, O and U and so there are 33 such letters.

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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.