Consider a simple project with exactly two activities - design and implementation. The design activity is scheduled to be started right away and takes 10 days to complete. The implementation activity, if started after the design activity is anticipated to take an additional 12 days. Each of these activities, it is assumed, is worked on by different people.

Our initial plan is to start implementation activity ONLY after the design is completed. Hence, the project is anticipated to take 10+12=22 days to complete. Moreover, we have to pay each person (both the person working on design and the person working on implementation $300 per day of work.

Hence, with this sequential schedule, it will cost us $300 x 22 = $6600 to complete the project.

After having learned about fast track project management (i.e., concurrent engineering), you decide that it might make sense to partially parallelize our design and implementation activity.