You get white light, the basic light colour you see every day.
Orange
Brown.
green
If you mix red, green, and yellow you will get a dark green bogey color!
blue
Brown
You get a light brownish colour.
Red is a base colour. You cannot mix it from other colours.
light green
You get a purple-brown color...
When you mix red, blue, and green light together, you get white light. This is because red, blue, and green are the primary colors of light, and when they are combined at full intensity, they create white light.
It does not matter how much red (a primary colour) and green (a secondary colour) you mix together, you will always get some variation of brown or grey. Yellow is a primary colour, that means you can not mix to get it. You can't do it. Yellow is a primay color which means that you can't mix colors to get yellow. Red is also a primary color and green is the complimentary color of red. When you mix these two colors you will get a strange shade of brown...but no yellow. Sorry.