Five Jobs Are Waiting for Processing Through Two Work Centres

Multiple Choice

Five jobs are waiting for processing through two work centres. Their processing time (in minutes) at each work centre is contained in the table below. Each job requires work centre Sigma before work centre Delta. According to Johnson's rule, what sequence of jobs will minimize the completion time for all jobs? $$\begin{array} { | c | c | c | } \hline \text { Job } & \text { Sigma } & \text { Delta } \\\hline R & 40 & 10 \\\hline \mathrm { S } & 25 & 30 \\\hline \mathrm { T } & 50 & 20 \\\hline \mathrm { U } & 35 & 35 \\\hline \mathrm { V } & 55 & 15 \\\hline\end{array}$$

A) R-S-T-U-V
B) S-V-T-R-U
C) S-U-T-V-R
D) V-R-U-S-T
E) none of the above