Which colours can be mixed to paint a violet flower?

Correct answer: Red and blue

On the traditional RYB colour wheel, mixing red and blue produces violet, a secondary colour. The other combinations lead to different results: yellow and blue make green, while red and yellow make orange. Green and yellow usually produce a yellow-green or other intermediate mixture rather than violet. The exact appearance depends on pigment quality and proportions, but red plus blue is the standard school-art answer for a violet flower.