1. The problem asks which equation correctly represents the surface area of a figure composed of two cubes, one with side length 5 cm and the other with side length 3 cm placed on top. 2. The surface area (S.A.) of a cube is given by the formula: $$\text{S.A.} = 6 \times \text{side}^2$$ 3. For two separate cubes, the total surface area would be the sum of their individual surface areas: $$6 \times 5^2 + 6 \times 3^2$$ 4. However, since the smaller cube is placed on top of the larger cube, the area of the face where they touch is not visible and should be subtracted once from the total surface area. 5. The area of the face where they touch is the area of the smaller cube's base: $$3 \times 3 = 9$$ 6. Therefore, the correct surface area equation is: $$6(5 \times 5) + 6(3 \times 3) - 3 \times 3$$ 7. This matches the equation: S.A. = 6(5 \cdot 5) + 6(3 \cdot 3) - 3(3)