Data indicate that the age of fines (i.e. number of days until paid) is normally distributed with a mean of 28 days and a standard deviation of 8 days.
a. Reminder letters will be sent to the oldest 15% of fines. How many days should a fine be outstanding before a reminder is sent?
b. The admin will give a discount to those fines paid by the 21st day. What percent will receive a discount?
