The Density of this Rectangular Prism would be 7.5, since the Volume of the Rectangular Prism can be determined by using the formula: length times width times height.
5*2*4, or 2*4*5, or 5*4*2= 40, because 5*2= 10, and 10*4= 40.
The Problem hereby, states that the mass of the Rectangular Prism is 300 grams, right?
Since the Formula for calculating the Density of an Object is Mass divided by Volume, 300 divided by 40 gives you 7.5, and we wouldn't make the answer 7.5 cubed, or 7.5 squared, or 7.5 grams cubed, or 7.5 grams squared, since squared would be for finding only the Area for 2-D Shapes, and cubed would be for finding only the Volume for 3-D Shapes, but in this case that we had here, We were finding Density, which includes Mass AND Volume, not just Volume.
