RGB values are a combination of three different numerical values which represent Red Green and Blue which range from 0 to 255. When combining two separate colors with RGB values you would simply need to add each of these numerical values together to form an entirely new RGB value. For example,
(105, 200, 0) + (203, 30, 186) = (255, 230, 186)
You can see in the example above that every number in the first color is added to the number in the same position within the second color. If the addition of two numbers goes above 255 then the value maxes out at 255 and stays as is.
