1
Part of 2011 IberoAmerican
Problems(2)
Problem 1, Iberoamerican Olympiad 2011
Source:
10/2/2011
The number is written on the board. Ana and Bruno play alternately. Ana begins. Each one, in their turn, replaces the number written by the one obtained by applying exactly one of these operations: multiply the number by , multiply the number by or add to the number. The first player to get a number greater than or equal to wins. Find which of the two players has a winning strategy and describe it.
combinatorics proposedcombinatorics
Problem 4, Iberoamerican Olympiad 2011
Source:
10/2/2011
Let be an acute-angled triangle, with and let be its circumcenter. Let and be points such that and are parallelograms. Show that is the orthocenter of .
geometryvectorparallelogramcircumcirclerhombustrigonometryperpendicular bisector