A fuel mixture requires 15% oil. How many liters of oil are needed for 80 L of fuel?

To determine how many liters of oil are needed in a fuel mixture that requires 15% oil for a total volume of 80 liters, you can apply the formula for finding a percentage of a quantity.

First, calculate 15% of 80 liters:

1. Convert the percentage to its decimal form by dividing by 100:

15% = 15/100 = 0.15.

2. Multiply the total volume of the mixture (80 liters) by the decimal form:

0.15 × 80 L = 12 L.

This calculation shows that for 80 liters of fuel, 12 liters of oil are required to meet the 15% oil concentration the mixture demands. Thus, 12 liters is the correct answer, as it directly aligns with what is needed based on the specified percentage, validating that it meets the condition of the fuel mixture requirement.