Suppose you want to implement a kanban system to control production of Part A, which is produced by Workstation X and used by Workstation Y at the rate of 30 units per hour. The part is stored in a storage area between the two workstations and managed by using a container of size 20 units. It takes 2 hours for Workstation X to produce a container of Part A. You have decided to set safety stock as 15% of needed inventory. How many containers do you need for the storage area between the two workstations