Following data refers to the jobs $$(P, Q, R, S)$$ which have arrived at a machine for scheduling. The shortest possible average flow time is ___________ days.

Four jobs are to be processed on a machine as per data listed in the table.

If the Earliest Due Date $$(EDD)$$ rule is used to sequence the jobs, the number of jobs delayed is

Four jobs are to be processed on a machine as per data listed in the table.

Using the Shortest Processing Time $$(SPT)$$ rule, total tardiness is

Six jobs arrived in a sequence as given below:

Average flow time (in days) for the above jobs using Shortest Processing Time rule is