Answer:
a. Value added time = Cutting time + Sewing time
Value added time = 5 minutes + 20 minutes
Value added time = 25 minutes
Non-value added time = Total within batch wait time + Move time
Non-value added time = [25 minutes * (40 - 1) + 2 minutes
Non-value added time = 977 minutes
Total lead time = Value added time + Non-value added time
Total lead time = 25 minutes + 977 minutes
Total lead time = 1,002 minutes
b. Value added ratio = Value added time / Total lead time
Value added ratio = 25 minutes / 1,002 minutes
Value added ratio = 0.02495
Value added ratio = 2.5%