The Lindell Corporation manufactures high-speed line printers for computer systems. The Lindell printers are compatible with most of the major computer vendors' hardware. Because of the intense competition in the marketplace for line printers and other peripherals, Lindell has made every attempt to make a high-quality printer. However, a recent production run of 20 printers contained two printers that tested out as defective (the other eighteen were fine). The problem was traced to a shipment of defective cable that Lindell received shortly before the production run started.

The production manager ordered that the entire batch of 20 printers be isolated from other production output until further testing could be completed. Unfortunately, a new shipping clerk packaged 10 of these isolated printers and shipped them to the California State Purchasing Department to fill an order that was already overdue. By the time the production manager noticed what had happened, the printers were already in transit.

The immediate concern was whether at least one of the defectives had been included in the shipment. The new shipping clerk thought there was a good chance that no defectives were included. What is the probability that no defectives were actually shipped? What is the probability at least one defective was shipped?