Kraft’s Kustom Kars is in the business of producing custom automobiles assemblies. In particular, Kraft operates a shop that builds and assembles the body and frame of the cars. Kraft’s operations begin with processing of initial paperwork. This must be done before any other operations are commenced. Once the paperwork has been completed, the body of the car can be built in Room A and the frame of the car can be built in Room B. When the body is built, it is transferred to Room C for finishing work. Similarly, when the frame is built, it is transferred to Room D for finishing work.
When both are built, although not necessarily finished the final paperwork can be completed. When both the body and frame are finished, they are transported to the assembly Room E, where the body is mounted to the frame.
In the frame building room, Room B, certain chemicals are used which must be completely eliminated by a thorough wash-down to prevent gaseous fumes from becoming a health hazard. The project is considered complete when the final paperwork has been completed, the body has been mounted to the frame, and Room B has been completely washed down.
The table below gives the expected completion times in hours for each activity of the project.
Activity Description Completion Time
A Initial Paperwork 3
B Build Body 3
C Build Frame 2
D Finish Body 3
E Finish Frame 7
F Final Paperwork 3
G Mount Body to Frame 6
H Room B Wash-down 2
1) Draw the PERT network that corresponds to this problem.
2) Find the earliest and latest start and finish times for each activity of the project. How long should the first project take?
3) Which activities must not be delayed if the project is to be completed in the time calculated in part (b)?
4) Suppose the body finish operation (D) were delayed four hours. By how much would the entire project be delayed?