olymmath

CMO 2003

Canadian Mathematical Olympiad 2003.

Paper

Problem 1

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  • Answer

Consider a standard twelve-hour clock whose hour and minute hands move continuously. Let mm be an integer, with 1≤m≤7201 \leq m \leq 720. At precisely mm minutes after 12:00, the angle made by the hour hand and minute hand is exactly 1∘1^{\circ}. Determine all possible values of mm.

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Problem 3

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Find all real positive solutions (if any) to

x3+y3+z3=x+y+z, and x2+y2+z2=xyz.\begin{gathered} x^{3}+y^{3}+z^{3}=x+y+z, \text { and } \\ x^{2}+y^{2}+z^{2}=x y z . \end{gathered}

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Problem 4

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Prove that when three circles share the same chord ABA B, every line through AA different from ABA B determines the same ratio XY:YZX Y: Y Z, where XX is an arbitrary point different from BB on the first circle while YY and ZZ are the points where AXA X intersects the other two circles (labelled so that YY is between XX and ZZ ).

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Problem 5

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Let SS be a set of nn points in the plane such that any two points of SS are at least 1 unit apart. Prove there is a subset TT of SS with at least n/7n / 7 points such that any two points of TT are at least 3\sqrt{3} units apart.

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