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.