job description along with a Job Specification

Dave Grubbs of Grubbs Auto Body has five cars waiting for Economy Detailing. An Economy Detailing consists of a wash and then a hand wax. Cars cannot be waxed until they are washed. ROUND UP (39/5) & (39/10).    Wash (hours) Wax (hours) (J)aguar 39/5 5 (C)adillac 5 3 (F)ord 1 39/10 (H)onda 2 1 (L)exus 4 4 What schedule produces the shortest time span in which these orders can be completed? Sequence:   ____ , _____ , _____ , ______ , ______   Create a Gantt chart for the optimal sequence (shortest time span).   How many hours does it take to complete the five orders?   For the schedule in question “a”, how many hours is the waxing task idle?   When will Dave finish the Cadillac?   What is the average order completion time?