20 customers are eating dinner at a local restaurant. The restaurant accepts cash or credit as forms of payment. Of the 20 customers, 4 have enough cash to pay for their meal, 16 have a credit card, and 3 have enough cash and a credit card. Using this information, answer each of the following questions. Let A be the event that a randomly selected customer has enough cash and B be the event that a randomly selected customer has a credit card.