When red and green are mixed, the resulting color depends on the context:
Additive Color Mixing (Light)
In light (e.g., screens), red and green combine to make yellow.
This is based on the RGB color model, used in digital displays.
Subtractive Color Mixing (Paint or Pigment)
In pigments (like paint), red and green mix to create a brown or a muddy neutral color.
The exact shade depends on the specific hues of red and green used.