In a salad/sandwich restaurant line, the following stations are there - Station A (Take Order), Station B (Make Sandwich/Salad), Station C (Condiments), Station D (Billing). The line works in series until it gets to Station C. Station C has two parallel stations that can both serve condiments at the same time. Station D is just a single station with both lines of Station C feeding into it. The rate for each station is as follows: Station A: 30 customers/hour Station B: 15 customers/hour Station C: 10 customers/hour each server (the two parallel stations are identical) Station D: 12 customers/hour The effective capacity (rate) of Station C is: The bottleneck of the system is