When we combine two colors, what results is a new color - a combination of both colors. The way we mix colors is through the primary colors - red, blue and yellow. When we mix these colors in different proportions, we get a wide variety of other colors.
When red and blue are mixed, they make purple. This is because red and blue are complementary colors, meaning they are located opposite from each other on the color wheel. When two complementary colors are combined, they make a new color. In this case, it's purple.
The way we mix the two colors determines how dark or light the shade of purple is. If we mix more red than blue, the purple is more of a red-violet. If we mix more blue, the purple is more of a blue-violet.
We can also mix purple with other colors to get different shades. For example, to get a rich, deep greenish-purple, we can mix purple with a bit of green.
So, to answer the question - why do two colors make purple? They do so because they are complementary colors, which means they are located opposite from each other on the color wheel. When two complementary colors are combined, they create a new color - in this case, purple.
For more information, you may want to check out this article:
https://www.thespruce.com/two-colors-make-purple-1327590
