2. A recent survey of a gas-station's customers showed that 68% paid with credit cards, 29% used debit cards, and only 3% paid with cash. During her eight-hour shift as cashier at this gas station, Serena had a total of 223 customer. What is the probability that... a. at least 142 customers used a credit card? b. fewer than 220 customers paid with credit or debit cards