Based on historical record, the average time before breakdown of a machine is considered to be normally distributed and has a mean of 26 weeks and a standard deviation of 10 weeks. It is estimated that the average cost resulting from a machine breakdown is $3,200. A machine breakdown can be prevented if preventive maintenance is performed in advance. Preventive maintenance costs $2,145 each time. What is the optimal preventive maintenance interval? A production line uses kanban system to control production and movement of parts. One work center uses an average of 600 parts per hour. The parts are delivered to the work center in containers. It takes an average of 20 minutes for a container to complete a cycle. Currently, 5 containers are assigned to this work center. If this number of containers is determined such that the work center operates with an inefficient factor of no greater than 0.25, how many parts does each container hold?
