The size of the model-sized cube VS the full-sized version can be compared using ratios:
15:127.5
We can find the scale by calculating 127.5/15, which equals to 8.5.
To find the area of one face, we do length*width. We know that the side length of the cube is 8.5cm, and since every side on the cube is the same, we do 8.5*8.5 which equals to 72.25cm^2.
To find the volume, we do length*width*height. As mentioned earlier, all sides of a cube are the same meaning the length, width and height are all 8.5cm.
8.5*8.5*8.5 = 614.125cm^3.