A piece of tin is in the form of a rectangle having length 12 cm and width 8 cm. This is used to construct a closed cube. The side of the cube is:
Answer & explanation
Answer: (c) 4 cm
The whole sheet of 12 × 8 = 96 cm² becomes the surface of the cube. A closed cube has six square faces, so 6s² = 96, s² = 16 and each side is 4 cm.
- Area of the sheet = 12 × 8 = 96 cm².
- Closed cube: 6s² = 96, so s² = 16 and s = 4 cm.
- Check: 6 × 4 × 4 = 96.
Remember · Sheet-to-solid problems: the sheet's area equals the surface area of the solid made from it.
Question and answer: UPSC's official GS Paper II (2016, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·