33rd Eötvös Competition 1929

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1.  Coins denomination 1, 2, 10, 20 and 50 are available. How many ways are there of paying 100?
2.  Show that ∑i=0 to k nCi (-x)i is positive for all 0 ≤ x < 1/n and all k ≤ n, where nCi is the binomial coefficient.
3.  L, M, N are three lines through a point such that the angle between any pair is 60o. Show that the set of points P in the plane of ABC whose distances from the lines L, M, N are less than a, b, c respectively is the interior of hexagon iff there is a triangle with sides a, b, c. Find the perimeter of this hexagon.

 

The original problems are in Hungarian. They are available on the KöMaL archive on the web. They are also available in English (with solutions) in: Andy Liu, Hungarian Problem Book III, 1929-1943, MAA 2001. ISBN 0883856441.

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© John Scholes
jscholes@kalva.demon.co.uk
6 January 2003
Last corrected/updated 2 Nov 03