Comentarii Jbmo 2015 -

Problem 3 (Geometry) was noted for its "attackability" through multiple different methods, including classic Euclidean geometry, vectors, and coordinate geometry.

A problem involving an acute triangle and perpendicular lines from a midpoint. The goal was to prove an equality between two angles, Comentarii JBMO 2015

The competition consisted of four problems covering algebra, number theory, geometry, and combinatorics. Problem 3 (Geometry) was noted for its "attackability"

. Notes indicate that many participants were able to solve this using analytical or vector methods. for positive real numbers

A significant majority (24 out of 28) of gold and silver medalists achieved a perfect score on Problem 1, confirming its low difficulty.

for positive real numbers. The minimum value was found to be 3.

A game-theory problem on a board involving L-shapes. It required determining the minimum number of marked squares needed to ensure a certain outcome. Key Commentary Insights