Four jobs are on order in a factory. As on day 20 of the production calendar, the corresponding due date and work remaining to complete these jobs (in days) are given in the table below.

$$ \begin{array}{|c|c|c|} \hline \text { Job } & \text { Due date } & \text { Work remaining (in days) } \\ \hline \text { M } & 26 & 5 \\ \hline \text { N } & 24 & 10 \\ \hline \text { O } & 28 & 10 \\ \hline \text { P } & 31 & 5 \\ \hline \end{array} $$

Which job(s) has/have critical ratio less than unity?

Parts P1 - P7 are machined first on a milling machine and then polished at a separate machine. Using the information in the following table, the minimum total completion time required for carrying out both the operations for all 7 parts is _______ hours.

Part	Milling (hours)	Polishing (hours)
P1	8	6
P2	3	2
P3	3	4
P4	4	6
P5	5	7
P6	6	4
P7	2	1

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