What happens when white and a little blue-green are added to red-orange?

Correct answer: The colour becomes lighter and less saturated

The governing concept is the difference between value and saturation. Adding white raises the value of red-orange, so it appears lighter and forms a tint. Blue-green, placed near the complementary side of red-orange, weakens its intensity when used in a small amount, so saturation decreases. The mixture does not become pure yellow or a primary colour; those distractors confuse colour adjustment with changing the colour category.