Determine the optimum preventive maintenance frequency for each of the pieces of equipment if breakdown time is normally distributed: Clearly label your calculations and describe using course related principles in 200 words. Equipment Avg Time (days)between breakdowns Standard Deviation Equipment Preventive Maintenance Cost Breakdown Cost A201 20 2 A201 $300 $2300 B400 30 3 B400 $200 $3500 C850 40 4 C850 $530 $4800