No two primary colors can make white, but any primary and it's complementary secondary color can, or indeed any color and its complementary color. Examples:
The secondary color needs about twice the intensity of the primary color because each of the above combinations should represent equal portions of the three primary colors, to appear white instead of a pale color.
https://www.quora.com/What-two-colors-make-the-color-white
You just need.... I DON'T KNOW
