Solution:
Step-1: Find the volume of the rectangular prism.
- Volume of rectangular prism: LBH
- => Volume of rectangular prism: (10)(2)(3 1/2)
- => Volume of rectangular prism: (10)(2)(3.5)
- => Volume of rectangular prism: (2)(35)
- => Volume of rectangular prism: 70 in³
Step-2: Find the volume of the small cube.
- Volume of cube: L³
- => Volume of cube: (1/2)³
- => Volume of cube: (1³/2³)
- => Volume of cube: (1/8)
Step-3: Divide.
- 70 ÷ 1/8
- => 70 x 8
- => 560 cubes
Thus, 560 cubes are needed to fill the rectangular prism.