Professional Image Briefcases is an exclusive producer of handcrafted, stylish cases. The company assembles each case with care and attention to detail. This laborious process requires the completion of the six primary work elements listed here.

Work Element Precedence Time (min)
A. Tan leather - - 30
B. Dye leather A 15
C. Shape case B 10
D. Mold hinges and fixtures -- 5
E. Install hinges and fixtures C, D 10
F. Assemble case E 10

a. Construct a precedence diagram for the manufacturing of briefcases.

b. Compute the flow time required for assembling one briefcase and the cycle time necessary to assemble 50 cases in a 40-hour week.

c. Balance the line and compute its efficiency.

d. How would you change the line to produce 80 cases per week?