Susan Williams has been the production manager of Medical Supplies, Inc. for the past 17 years. Medical Supplies Inc. is a producer of bandages and arm slings. During the past 5 y ears, the demand for No-Stick bandages has been fairly constant. On the average, sales have been about 87,000 packages of No-Stick. Susan has reason to believe that the distribution of No-Stick follows a normal curve, with a standard deviation of 4,500 packages. a. What is the probability that sales will be less than 80,000 packages?