In a 100-gallon mixture with a rate of 3 pounds per 100 gallons, how many pounds are required?

• A. 1 pound
• B. 2 pounds
• C. 3 pounds
• D. 4 pounds

Answer: (C)

When you have a rate stated as X pounds per 100 gallons, the amount of pounds needed changes in direct proportion to the number of gallons. So for 100 gallons, you use the rate exactly as given: 3 pounds per 100 gallons means 3 pounds are required for 100 gallons. The calculation is pounds = rate × (gallons/100) = 3 × (100/100) = 3. If the volume were different, the pounds would scale accordingly (for example, 200 gallons would need 6 pounds, 50 gallons would need 1.5 pounds).