Which colour combines with the primary colour red to make orange?

Correct answer: Yellow

In traditional subtractive paint mixing, red and yellow combine to produce orange, so yellow is the correct answer. The governing rule is the secondary-colour pair: red plus yellow equals orange. Red mixed with blue generally produces violet, while green and violet are already secondary colours rather than the required primary partner. The exact result can vary with pigments, but the standard school art-theory relationship clearly identifies yellow.