Efficiency of a car engine measured by an engineer is found to be 12% in an experiment. After the experiment, it was found that the petrol used was duplicate having 4% lesser efficiency than pure petrol. If petrol is used, then find actual efficiency of car.

Q: Efficiency of a car engine measured by an engineer is found to be 12% in an experiment. After the experiment, it was found that the petrol used was duplicate having 4% lesser efficiency than pure petrol. If petrol is used, then find actual efficiency of car.

(a) 8%

(b) 12%

(c) 12.5%

(d) 25%