Area of the four walls — Mensuration Aptitude Question
Area of the four walls: What is the area of the four walls of a room 8 m long, 6 m wide and 4 m high? Answer and worked solution on CodeKairo.
- Topic: Mensuration
- Section: Quantitative Aptitude
- Difficulty: Medium
- Time target: 60 seconds
Question
What is the area of the four walls of a room 8 m long, 6 m wide and 4 m high?
Options
- 96 m²
- 112 m²
- 128 m²
- 144 m²
Show the answer and the worked solution
Correct answer: B. 112 m²
Worked solution
- Area = 2(8 + 6) × 4 = 2 × 14 × 4 = 112 m².
Answer: 112 m².
The idea
The four walls form a band of height h around a perimeter of 2(l + b). The floor and ceiling are excluded.
Shortcut. Two 8 × 4 walls (64) and two 6 × 4 walls (48) make 112 m².
Common trap. 128 m² — treating all four walls as 8 m × 4 m; two of them are only 6 m wide.