If a lawn requires 4 gallons per 1,000 square feet, how many gallons are needed to treat 8,000 square feet?

If a lawn requires 4 gallons per 1,000 square feet, how many gallons are needed to treat 8,000 square feet?

• A. 16 gallons
• B. 32 gallons
• C. 40 gallons
• D. 48 gallons

Answer: (B)

Direct proportionality between area and the amount needed. If 4 gallons cover 1,000 square feet, the amount scales directly with area. 8,000 square feet is eight times larger than 1,000, so you need eight times as much product: 4 gallons × 8 = 32 gallons. You can also see it with the per-square-foot rate: 4 gallons per 1,000 sq ft equals 0.004 gallons per sq ft; 8,000 sq ft × 0.004 = 32 gallons. So 32 gallons are required. For context, 4,000 sq ft would need 16 gallons, 10,000 sq ft would need 40 gallons, etc.

Direct proportionality between area and the amount needed. If 4 gallons cover 1,000 square feet, the amount scales directly with area. 8,000 square feet is eight times larger than 1,000, so you need eight times as much product: 4 gallons × 8 = 32 gallons. You can also see it with the per-square-foot rate: 4 gallons per 1,000 sq ft equals 0.004 gallons per sq ft; 8,000 sq ft × 0.004 = 32 gallons. So 32 gallons are required. For context, 4,000 sq ft would need 16 gallons, 10,000 sq ft would need 40 gallons, etc.