Given the following chart of jobs assigned with Johnson's rule suppose that all the jobs (A, B, C, etc) could be evenly divided into two tasks (such as A1 and A2, B1 and B2, etc). Suppose job B is divided into jobs B1 and B2, each with a body work time of 4.5 hours and a paint time of 2 hours. How much is makespan reduced by this splitting of B?

Johnson's Rule

A sequencing rule used to minimize job or project completion time by ordering tasks based on the shortest processing time at a given workstation.

Makespan

The total time required to complete a set of tasks or jobs from start to finish in production or project scheduling.

Body Work Time

refers to the time spent repairing or modifying the body of vehicles in automotive repair.