If a label provides a rate of 3 pounds per 100 gallons of water, how many pounds are needed to prepare 200 gallons of finished spray?

• A. 3 pounds
• B. 4 pounds
• C. 6 pounds
• D. 9 pounds

Answer: (C)

Scaling a label rate proportionally with the volume is the key idea here. The label calls for 3 pounds for every 100 gallons. If you double the amount of water from 100 gallons to 200 gallons, you must also double the chemical to keep the same concentration. So you’d need 3 pounds × 2 = 6 pounds.

If you prefer the math: the rate is 3 lb per 100 gal, which is 0.03 lb per gallon. For 200 gallons, 0.03 × 200 = 6 pounds.

Using another way to think about it, 3 pounds covers 100 gallons, so 200 gallons would require twice as much, i.e., 6 pounds.