Suppose a quality manager for Dell Computers has collected the following data on the quality status of disk drives by supplier. She inspected a total of 700 disk drives.

Drive Status Supplier Working Defective Company A 120 10 Company B 180 15 Company C 50 5 Company D 300 20

a. Based on these inspection data, what is the probability of randomly selecting a disk drive from company B?

b. What is the probability of a defective disk drive being received by the computer company?

c. What is the probability of a defect given that company B supplied the disk drive?