The carpet leaves a 1 m margin on all sides, so subtract 2 m from each dimension to get the carpet area.

• Carpet length = 31 − 2 = 29 m
• Carpet width = 18 − 2 = 16 m
• Carpet area = 29 × 16 = 464 m²
• Cost = 464 × $21 = $9744

Final Answer: $9744