37th Eötvös Competition 1933

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1.  If x2 + y2 = u2 + v2 = 1 and xu + yv = 0 for real x, y, u, v, find xy + uv.
2.  S is a set of 16 squares on an 8 x 8 chessboard such that there are just 2 squares of S in each row and column. Show that 8 black pawns and 8 white pawns can be placed on these squares so that there is just one white pawn and one black pawn in each row and column.
3.  A and B are points on the circle C, which touches a second circle at a third point P. The lines AP and BP meet the second circle again at A' and B' respectively. Show that triangles ABP and A'B'P are similar.

 

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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(C) John Scholes
jscholes@kalva.demon.co.uk
6 January 2003
Last corrected/updated 6 Jan 03