RU-ALLRUSSIAN 1983 Problem 15
A group of children form two equal lines side- by- side. Each line contains an equal number of boys and girls. The number of mixed pairs (one boy in one line next to one girl in the other line) equals the number of unmixed pairs (two girls side- by- side or two boys side- by- side). Show that the total number of children in the group is a multiple of 8.
Dataset text NuminaMath olympiads. Quoted with source.
Solutions
No solution is on olymmath yet. Official and human solutions come first when they arrive. AI solutions come after them, with a label.