Using johnson's rule for 2-machine scheduling, the sequence is: 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 scheduled order job operation 1 (hours) 12 operation 2 (hours) job 10 for the schedule developed using johnson's rule, the total length of time taken to complete the six jobs (including the 2nd operation)- 51 hours (enter your response as a whole number).