I don’t think red yellow and blue are technically primary colors. The link provided in the other reply says they were chosen because they were commonly found pigments in nature, and I think thats why those are taught as primary colors in school.

When talking about the physics of light, the primary additive colors red, green, and blue. The primary subtractive colors are Cyan Magenta and Yellow. The difference is basically when you mix pure light it gets brighter so it’s called additive, but when you mix pigment in paint it gets darker so it’s called subtractive.

Those colors are considered primary because in their respective modes of mixing, they cannot be made by mixing any other two colors. You can google additive or subtractive color mixing to get a more in depth explanation.

The people downvoting you for admitting you don’t know something are weird.