How are complementary colours made?

The complement of any primary color can be made by combining the two other primary colors. For example, to achieve the complement of yellow (a primary color) one could combine red and blue. The result would be purple, which appears directly across from yellow on the color wheel.

the complementary of any primary colour can be made by combining the two others primary colour

including the octave, the answer would 8 notes in a major scale with one note being played twice. ex) c major scale includes: c, d, e, f, g, a, b, c

notice that c is played twice

however, if you were to ask me how many different notes are in a major scale- the answer would be 7.