The quality control department examines all the products returned to a store by customers. An examination of the returned products yields the following assessment: 5% are defective and not repairable, 45% are defective but repairable, 35% have small surface scratches but are functioning properly, and 15% have no problems. Compute the following probabilities for a random sample of 20 returned products:
a. All of the 20 returned products have some type of problem.
b. Exactly 6 of the 20 returned products are defective and not repairable.
c. Of the 20 returned products, 6 or more are defective and not functioning properly.
d. None of the 20 returned products has any sort of defect.