A small grocery store has a total of four regular checkout lines and one express checkout line. Recently on Sundays the store has been experiencing either excessive idle time for cashiers or excessively long customer waiting lines. The results of a recent time study performed by a management consulting company showed that the average service time for express and regular checkout lines are 3 and 10 minutes respectively. As the next step in analyzing the problem, the manager of the grocery store wants to determine the estimated capacity of the store on Sundays in terms of total number of customers. Currently the store is open from 6 a.m. to midnight on Sundays. The express checkout line is always open while there is only one regular line open from 6 a.m. to 9 a.m. and also one regular line open from 9 p.m. to midnight. There are two regular checkout lines open from 9 a.m. to noon and also from 6 p.m. to 9 p.m. All four regular lines are open between noon and 6 p.m.
a. Determine the current capacity of the store in total number of customers for Sundays.
b. Assume that the store manager decides to reduce the number of regular lines from 2 to 1 between 7 p.m. and 9 p.m. and closes the express line between 6 a.m. and 8 a.m. and 10 p.m. and midnight. What is the revised capacity for Sundays?