. Notes indicate that many participants were able to solve this using analytical or vector methods.
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
Problem 1 was criticized for being perhaps too simple for an international olympiad, acting more as a "points booster" than a differentiator for top talent. confirming its low difficulty.
. Commentary suggests this was a very accessible problem, possibly even at a 5th or 6th-grade level, which resulted in a high number of maximum scores. Comentarii JBMO 2015
A significant majority (24 out of 28) of gold and silver medalists achieved a perfect score on Problem 1, confirming its low difficulty.