Using Johnson's rule for $2-$machine scheduling, the sequence is:

$\backslash$table$[[$Scheduled Order,Job$],[1,$A$],[2,$F$],[3,$E$],[4,$B$],[5,$D$],[6,$C$]]$

For the schedule developed using Johnson's rule, the total length of time taken to complete the six jobs $($including the $2$ nd operation$)=$ hours $($enter your response as a whole number$).$

Six jobs are to be processed through a two$-$step operation. The first operation involves sanding, and the second involves painting. Processing times are as follows:

$\backslash$table$[[$Job$,\backslash$table$[[$Operation$],[1($hours$)]],\backslash$table$[[$Operation$],[2($hours$)]]],[$A$,1,3],[$B$,10,12],[$C$,8,7],[$D$,11,9],[$E$,4,6],[$F$,2,13]]$