A product requires two sequential machine operations. The first takes 4 minutes and the defect rate is 8%. The second takes 5 minutes and the defect percentage is 5%.
Assuming factory operates 300 days/ year; a daily shift of 8 hours. Find the number of machines we need to manufacture 50,000 units per year.
History shows production takes 2000 hours due to setup and 1,600 hours due to machine unavailability (maintenance needs)