The answer is: 5,614 square inches.
The explanation is shown below:
1. The gift on the bottom is a rectangular prism. To calculate its surface area, you must apply the following formula:
Where is the length (20 inches),
is the width (42 inches) and
is the heigth (16 inches).
2. Substitute values:
3. The surface area of the other gifts can be calculated with the formula for calculate the surface area of a cube:
Where is the side.
4. The surface area of the bigger cube is:
5. The surface area of the smaller cube is:
6. The total surface area (the combined surface area of the three gifts) is: