Colour alignment

50 applicants were placed into a darkened room, each with a coloured baseball cap upon their head. These baseball caps came in two colours, red and green, however no applicant knew the colour of their own cap. The applicants were not allowed to communicate in anyway. Their task was to assemble outside, in a line, with those wearing red caps on one side and those wearing green on the other. How to achieve this?


Answer:

The first two stood out anywhere they liked. The next applicant looked at the line, if all of the caps were the same colour, they stood at either end of the line. Otherwise they stood at the position where the colours of the caps changed from red to green. The procedure was repeated until every body took his turn.