I'm pretty sure you are right when talking about the primary colors of light however in the art world I believe the colors are red blue and yellow.
Well, that is an interesting subject. The historical primary colors for art are red blue and yellow, but modern studies have shown that magenta cyan and yellow are much more correct and useful.
People still teach red blue and yellow, so I can't really blame people for thinking that, but they technically aren't primary colors. EDIT: Of course with the exception of yellow.