A Color problem.

Red, Yellow, Blue are subtractive primaries.

Red, Blue, Green are additive primaries.

If that is the answer, then I am not sure how it is a brain teaser.

 

I don't know the rules either, I just thought brain teasers are something that can be figured out (logically) if you think about it, and this was more of either you know it or you don't. Either way, I don't see any harm in posting it.

 

A third set, what about cyan, yellow, and magenta?

 

How would you define primary colors? This is something like vectors. Using a combination of any three non coplanar vectors, you can define any vector in a particular 3D space.

In the same way, using a combination of any three different colors you could get all other colors I guess. In different quantities. Although one would have to be white, and of the other two, one dark and one light.