public int addFuelToCar(int litresAdded) {
        if(isCarRented() == false || getFuelInCar() == getFuelCapacity()){
			return 0;
		} else {
        int fuelTotal = fuelInCar + litresAdded;
		int fuel = Math.min(fuelTotal, fuelCapacity);
		fuelInCar = fuel;
		if (litresAdded >= (fuelCapacity - fuelInCar)){
			return fuelCapacity - fuelInCar;
		} else {
		return litresAdded;
		}
	  }
   }