Answer: 3.75 cubic units.
Step-by-step explanation:
Each cube has side length 1/2. The volume of each smaller cube is (1/2)^3 = 1/8 cubic units.
The box holds 2 layers and 15 cubes per layer. There are 2*15 = 30 cubes total. The total volume of all 30 cubes is 30*(1/8) = 30/8 = 15/4 = 3.75 cubic units, which also represents the volume of the box.