Efficiency = (Useful Energy Output / Total Energy Input) x 100%
* Useful Energy Output: 15 units
* Total Energy Input: 50 units
Efficiency = (15 / 50) x 100% = 30%
Therefore, the car has an efficiency of 30%. This means that only 30% of the energy put into the car is converted into useful work, while the remaining 70% is lost as heat, sound, or other forms of energy.
