Question

an electric car advertises it is 80% energy efficient and a comparable gasoline car is 15% efficient. what does this mean? (1 point)
electric cars account for 80% of the total electricity used, while gasoline cars account for 15% of the gasoline used.
80% - 15% = 65%, so the electric car has 65% more capacity than the gasoline car and can drive longer.
80% of the energy used by the electric car results in breathable air, while 15% of the energy used by the gasoline car results in breathable air.
80% of the electrical energy turns the wheels, while 15% of the gasoline energy turns the wheels.

Explanation:

Energy efficiency in cars refers to the proportion of input energy that is converted into useful work (like moving the wheels). For the electric car, 80% of the electrical energy it takes in is used to turn the wheels (useful work). For the gasoline car, only 15% of the gasoline energy (input energy) is used to turn the wheels. The other options are incorrect. The first option misinterprets efficiency as a proportion of total energy used in a general sense (not about conversion to useful work). The second option wrongly subtracts efficiencies to talk about capacity (efficiency is about energy - to - work conversion, not capacity). The third option has no relation to breathable air (efficiency is about mechanical work from energy, not air quality).

Answer:

80% of the electrical energy turns the wheels, while 15% of the gasoline energy turns the wheels.