Customers arrive at a KFC drive-thru at an average rate of 5 customers per hour.

1. Find the probability that more than 15 customers arrive in two hours.

2. Let your random variable be the time between consecutive arrivals. Find the probability that if a customer has just arrived, it will take between 15 and 25 minutes before the next customer arrives.

3. Let your random variable be the time between consecutive arrivals. Suppose that 10 minutes have elapsed since the previous customer has arrived. What is the probability that the next customer will arrive within the next 15 minutes?

4. Suppose that the time in hours between consecutive arrivals is greater than with a probability of 0.006738. Find . (Integer value)