You are trying to arrange the machines that make your "widgets" more efficiently. Your ONE assembly line operates 8 hours a day and makes 400 widgets per day.
You have a diagram in front of you that shows how work must flow (the time it takes to complete the task is in seconds). THIS IS ONE ASSEMBLY LINE, NOT THREE; I'M JUST SHOWING THE TASKS THAT NEED TO BE DONE AND IN WHAT ORDER THEY NEED TO BE ACCOMPLISHED SO THAT YOU CAN CREATE THE ASSEMBLY LINE.
Task A (32) --- Task D (8) -------Task G (20) -------Task J (28) --------Task L (36)
Task B (36)--------Task E(29) --------Task H(17)---------Task K (32)
Task C (24)--------Task F(32) --------Task I (38)
1. Find the cycle time in SECONDS because the tasks are in seconds.
Cycle time formula (represented by the letter C): Production Time Per Day (IN SECONDS) divided by Output Per Day
2. Find the theoretical number of workstations (represented by the letter W)
Theoretical number of work stations formula: Time of all the tasks' added together (represented by the letter T) divided by the cycle time (this will not be an even number...round UP to the next whole number (you can't have .45 of a workstation). The formula can be expressed as T/C
3. Group the tasks into theoretical workstations: You're just trying to get workstations grouped so that the total time of a particular station doesn't go over the cycle time; so if the cycle time was 67 seconds (this is not the correct answer) then you couldn't group A and B together into a workstation because it would be 68 seconds. Now please, you're just trying to get the TIME correct... Tasks C, F and I don't have to be grouped together just because they flow that way. Just group the tasks together so they are less than the cycle time. Remember, you have the total number of workstations from question two.
4. Find the efficiency:
Efficiency formula: Time of all the tasks (T) divided Workstations (W) times Cycle Time (C) or T/WxC