Johnson$$s Rule Problem. Given the operation times in the two$-$work$-$centre

flow shop below:

Job Times $($Minutes$)$

Job Work Centre $1$ Work Centre $2$

A $2027$

B $1630$

C $4351$

D $6012$

E $3528$

F $4224$

Requirements:

$($a$)$ Develop a job sequence that minimizes total idle time at Work Centre $2.$

$($b$)$ Construct a load Gantt chart for the activities at the two work centres, and determine

work centre $2$s idle time.