Answer: 1: red and blue
2: red and yellow
Explanation: When you mix two primary colors, you get a secondary color. When you mix a primary color with a secondary color, you get a tertiary color. For example, mixing red and blue will give you purple which is a tertiary color. Similarly, mixing red and yellow will give you orange which is also a tertiary color.
Yellow and blue or yellow and green are already secondary color, mixing them will not result in tertiary color.