Answers:
V = 30 cubic cm
D = 4 grams per cubic cm
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Step-by-step explanation:
The volume of a rectangular solid (aka block or brick) is equal to its length times width times height
V = length*width*height
V = 5*2*3
V = 10*3
V = 30 cubic cm
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You haven't mentioned it, but the "D" probably refers to the density. This is a measure how much stuff occupies a certain volume of space. The higher the density, the more stuff in that space. Think of it like cramming more packing peanuts in a box.
To find the density, we divide the mass over the volume
density = mass/volume
density = (120 grams)/(30 cubic cm)
density = 4 grams per cubic cm
In each cubic centimeter of space, there are 4 grams of mass.