Moisture content per gram of a certain baked product has specification limits of 120 mg and 160

Question:

Moisture content per gram of a certain baked product has specification limits of 120 mg and 160 mg. Find the Cp and Cpk capability indexes if
(a) The process mean is 140 mg and the process standard deviation is 5 mg; and
(b) The process mean is 140 mg and the process standard deviation is 3 mg.