please explain the answers

Problem \# 1: Use the SPT rule and calculate the average flow-time and waiting time of the jobs given in Table 1A. (Note: Flow-time is the same as completion time.) (1) What is the total processing time of the jobs? (a) 48 (b) 44 (c) 42 (d) 51 (2) What is the average flow-time of the jobs? (a) 16.3 (b) 23.6 (c) 27.8 (d) 17.4 (3) What is the average waiting time of the jobs? (a) 11.9 (b) 16.2 (c) 13.4 (d) 8.8 (4) At what hour was job A finished? (a) 24 (b) 20 (c) 17 (d) 18 (5) At what hour was job C started? (a)32(b)51(c)20(d)19 (6) What was the waiting time for job E? (a) 19 (b) 20 (c) 12 (d) 4 (7) What was the waiting time for job A? (a) 11 (b) 7 (c) 4 (d) 19 Problem \#2: Use the EDD rule to schedule the jobs and calculate the completion time, and tardiness or delay in days for each job. (8) What is the total processing time of the jobs (in days)? (a) 41 (b)53(c)47(d)59 (9) On what day was job J finished? (a) 44 (b) 40 (c)37(d)48 (10) On what day was job N started? (a) 13 (b) 16 (c) 23 (d) 19 (11) On what day was job M finished? (a) 11 (b) 14 (c) 29 (d) 16 (12) On what day was job K started? (a) 11 (b) 14 (c) 29 (d) 16 (13) What is the tardiness or delay in completing job M? (a) 8 (b) 4 (c) 0 (d) 5 (14) What is the tardiness or delay in completing job J? (a) 9 (b) 6 (c) 2 (d) 3 (15) What is the tardiness or delay in completing job L? (a) 2 (b) 5 (c) 7 (d) 4 Problem \#3: Use Johnson's rule, develop a processing sequence and calculate the minimum makespan for the jobs given in Table 3A. (16) What is the total processing time of the jobs on machine 1 ? (a) 28 (b) 23 (c) 24 (d) 19 (17) What is the total processing time of the jobs on machine 2 ? (a) 25 (b) 20 (c) 27 (d) 18 (18) At what hour was job R started on machine 2? (a) 0 (b) 2 (c) 6 (d) 3 (19) At what hour was job T finished on machine 2? (a) 12 (b) 13 (c) 11 (d) 9 (20) At what hour was job P started on machine 2? (a) 13 (b) 11 (c) 19 (d) 15 (21) What was the amount of idle time on machine 2 between the completion of job T and starting of job P? (a) 0 (b) 2 (c) 8 (d) 5 (22) At what hour was job P finished on machine 2? (a) 11 (b) 13 (c) 24 (d) 19 (23) At what hour was job S started on machine 2? (a) 23 (b) 21 (c) 18 (d) 26 (24) What was the amount of idle time on machine 2 between the completion of job P and starting of job S? (a)0(b)3(c)2 (d) 7 (25) What is the total amount of idle time on machine 2? (a) 5 (b) 4 (c) 8 (d) 6