A bank is interested in studying the number of people who use the ATM located outside its office late at night. On average, 1.6 customers walk up to the ATM during any 10-minute interval between 9pm and midnight. a) What is the probability of exactly 2 customers using the ATM during any 10-minute interval? b) What is the probability of 2 or more customers using the ATM during any 10-minute interval?