Is it possible to get a volume of 12000 cm3 with a surface area between 3200 cm3 and 4000 cm2?
I have tried 60 x 20 x 10, 50 x 20 x 12, 100 x 12 x 10 and haven't even gotten close to the surface area that I need.
You can try with : 30 x 40 x 10. Volume is 12000 and the surface area: 2*30*40 + 2*30*10 + 2*40*10 = 2400 + 600 + 800 = 3800. This is a surface area between 3200 cm² and 4000 cm².