Which tertiary colour is made by combining the secondary colour orange with the primary colour yellow?

Correct answer: Yellow-orange

The governing concept is tertiary-colour formation: a tertiary colour is produced by mixing one primary colour with a neighbouring secondary colour on the colour wheel. Yellow is primary and orange is secondary; because their names are joined in the mixture, the result is yellow-orange. Red-orange would require red with orange, while yellow-green requires yellow with green.