Why are the olympic rings those colors?

The five interlocking rings represent five continents or major geographical areas of the world. The five main regions: Africa, the Americas (North and South America are combined), Asia, Europe and Oceania. As it says in the Olympic Charter, the five-ringed symbol "represents the union of the five continents and the meeting of athletes from throughout the world at the Olympic Games." The colors of the rings represent the flags of the countries that participate in the Olympics. Every flag of a country participating in the Olympics includes at least one of the following colors: blue, black, red, yellow, and green.

Baron Pierre de Coubertin conceived the design of both the rings and the flag. The Olympic Committee adopted the flag in 1914, and it was first flown at the 1920 Antwerp Games.