3. In a bank operation, the arrival rate is 2 customers per minute. Determine the following:

(a) The average number of arrivals during 5 minutes.

(b) The probability that no arrivals will occur during the next .5 minute.

(c) The probability that at least one arrival will occur during the next .5 minute.

(d) The probability that the time between two successive arrivals is at least 3 minutes.