Wednesday, October 13, 2010

25th Eötvös Competition Problems 1918

1.  AC is the long diagonal of a parallelogram ABCD. The perpendiculars from C meet the lines AB and AD at P and Q respectively. Show that AC2 = AB·AP + AD·AQ. 2.  Find three distinct positive integers a, b, c such that 1/a + 1/b + 1/c is an integer.