Given 99% as the reliability of an ATM1 (which is the only one in our ATM center):
a. What is the total amount of time (in minutes) that it is expected NOT to work in a 30-day month?
b. If the cost of each additional ATM is $5K, at what cost can we increase the reliability of our ATM center to 99.9999%? (Use the serial/parallel configuration.)