The corrosion potential of iron immersed in a de-aerated acidic solution of pH = 3 is -0.720 V as measured at 25°C relative to the standard calomel electrode with potential 0.2802 V. A Tafel plot of catholic current density against over potential yields a slope of 18 V-I and the hydrogen ion exchange current density jo = 0.10 μA cm-2. Calculate the corrosion rate in milligrams of iron per square centimeter per day (mg cm-2 d-l).