At Apple's assembly plant in China, the assembly line for iPad motherboards has a demand for 500 units an hour. Two feeder lines supply parts A and B to the assembly line (one A and one B for each motherboard). Standard divided container trays are used. A container will hold 40 As or 200 Bs. It takes 20 minutes to fill up a container with As and 30 minutes to fill up a container with Bs. Transit time to the assembly cell is 10 minutes for both A and B. The safety factor is set at 10 percent. Set up a kanban control system for the assembly process.