What is the formula for gallons per acre (GPA)?

What is the formula for gallons per acre (GPA)?

• A. GPA = 340 × N × A / W × L.
• B. GPA = 400 × N × A / W × L.
• C. GPA = 340 × N × A × W × L.
• D. GPA = 340 ÷ (N × A) × W × L.

Answer: (A)

Calculating gallons per acre hinges on how much liquid your sprayer produces, how many application points you’re using, and how much ground you cover in a pass. The constant 340 represents a unit-conversion factor that makes the math come out in gallons per acre when you account for the number of nozzles (N) and the area each nozzle sprays (A). You multiply N by A because more nozzles or more area per nozzle increases the total spray delivered. You then divide by the spray swath you move through per pass (the width times the length, W × L); as that swath grows, the same total flow covers more acres, so GPA goes down. This setup correctly represents how GPA scales with each factor. The other forms would either misplace the division or place the swath in the numerator, which would incorrectly imply GPA increases with greater travel area or misalign the units.

Calculating gallons per acre hinges on how much liquid your sprayer produces, how many application points you’re using, and how much ground you cover in a pass. The constant 340 represents a unit-conversion factor that makes the math come out in gallons per acre when you account for the number of nozzles (N) and the area each nozzle sprays (A). You multiply N by A because more nozzles or more area per nozzle increases the total spray delivered. You then divide by the spray swath you move through per pass (the width times the length, W × L); as that swath grows, the same total flow covers more acres, so GPA goes down. This setup correctly represents how GPA scales with each factor. The other forms would either misplace the division or place the swath in the numerator, which would incorrectly imply GPA increases with greater travel area or misalign the units.