If an insecticide label requires 20 fluid ounces to cover 1,000 square feet, and you apply 2 gallons of water to a 250-square-foot area, how many fluid ounces of insecticide are needed per gallon of water?

If an insecticide label requires 20 fluid ounces to cover 1,000 square feet, and you apply 2 gallons of water to a 250-square-foot area, how many fluid ounces of insecticide are needed per gallon of water?

• A. 1.25 ounces
• B. 2.5 ounces
• C. 5 ounces
• D. 10 ounces

Answer: (B)

The amount of insecticide scales with the area, then with the amount of water used. The label gives 20 fluid ounces for 1,000 square feet, which is 20/1000 = 0.02 fluid ounces per square foot. For a 250-square-foot area, you need 250 × 0.02 = 5 fluid ounces of insecticide in total. You’re applying this with 2 gallons of water, so the insecticide per gallon of water is 5 ounces divided by 2 gallons = 2.5 ounces per gallon.

The amount of insecticide scales with the area, then with the amount of water used. The label gives 20 fluid ounces for 1,000 square feet, which is 20/1000 = 0.02 fluid ounces per square foot. For a 250-square-foot area, you need 250 × 0.02 = 5 fluid ounces of insecticide in total.

You’re applying this with 2 gallons of water, so the insecticide per gallon of water is 5 ounces divided by 2 gallons = 2.5 ounces per gallon.