Guy's, I have a box of Duncan Hines cake mix, can I make brownies out of it?

Hi, I thought it would be cheaper doing it this way can I make brownies out of the duncan Hines cake mix? this cake recipie calls for: 11/3 C.Water, 1/2 C.veg. oil, and three large eggs. Is there someone who can give me the right exact measurements to turn this cake mix into delicious brownies please and if so what temp. and how long does this bake for and thank you very much for your help and time.