QUESTION 1: A sales counter at a particular departmental store is open for two hours every evening from 4.00 PM to 6.00 PM. The counter is served by one sales person who provides an integrated service of serving customers, preparing bills and collecting payments. There have been complaints from customers of poor service and long waiting times. Management decided to study the system by simulation. It collected the following data over the two-hour period on a particular day.

QUESTION 2: A manufacturer of screw fasteners found that there was a market for packages of mixed screw sizes. His market researcher advised that two mixtures (A and B) of three screw types (1, 2 and 3), properly priced, would be most acceptable to the buyer. The relevant data is displayed in the table below.

The plant capacity and production costs are given in the table below.

What production should the manufacturer schedule in order to maximize total profit assuming that he can sell all that he manufactures? Provide complete details of all your calculations.

QUESTION 3 An engineering company has secured a contract to supply a steel fabrication with a target duration of 60 days. The tasks have been analyzed as follows

3.1 Draw a simple, activity-on-node, network diagram of this project.

3.2 Prepare an activity schedule (in tabular form) showing the early and late start and finish times as well as the slack times.

3.3 Identify the critical path.

3.4 What is the normal project completion time.

3.5 After completion of work on day 23, a fire broke out and destroyed all work done on task C and the work-in progress on tasks G and H. Fortunately no other completed tasks were affected, but it is estimated that task M will now need 15 days. The project manager thinks that after the fire there will be variability in the task times and has made the following uncertainty estimates.

3.5.1 Draw a network diagram of the revised project. 

3.5.2 Determine the revised critical path and project completion time

3.5.3 Calculate the probability of completing the project on time after the fire.