Table J.12
Consider the following problems in which six jobs must each be processed on two machines starting with machine 1 and then going to machine 2.The following processing times and due dates are in hours.

-Use the information in Table J.12.Use Johnson's rule to schedule the jobs.How long does job B wait after finishing on Machine 1 before starting on Machine 2?
A)fewer than or equal to 5 hours.
B)more than 5 hours but fewer than or equal to 10 hours
C)more than 10 hours but fewer than or equal to 15 hours
D)more than 15 hours but fewer than or equal to 20 hours

Question

Table J.12
Consider the following problems in which six jobs must each be processed on two machines starting with machine 1 and then going to machine 2.The following processing times and due dates are in hours.
 
-Use the information in Table J.12.Use Johnson's rule to schedule the jobs.How long does job B wait after finishing on Machine 1 before starting on Machine 2?
A)fewer than or equal to 5 hours. 
B)more than 5 hours but fewer than or equal to 10 hours 
C)more than 10 hours but fewer than or equal to 15 hours 
D)more than 15 hours but fewer than or equal to 20 hours

Quizplus · Accepted Answer

Using Johnson's rule, we first look for the smallest processing time for each job.

1. Job E: Smallest time is on Machine 2 (2 hours)
2. Job A: Smallest time is on Machine 1 (3 hours)
3. Job B: Smallest time is on both machines (4 hours each)
4. Job C: Smallest time is on Machine 2 (3 hours)
5. Job D: Smallest time is on Machine 1 (2 hours)
6. Job F: Smallest time is on Machine 1 (1 hour)

So the order in which we will schedule the jobs is: F, D, A, B, E, C

To find how long job B waits after finishing on Machine 1 before starting on Machine 2, we need to look at the processing times of the jobs before and after B on each machine:

- Job D on Machine 1 has a processing time of 2 hours
- Job A on Machine 2 has a processing time of 5 hours
- Job B on Machine 2 has a processing time of 4 hours

So job B will wait for 5 hours (2 hours for Job D on Machine 1 + 3 hours for Job A on Machine 2) before starting on Machine 2. Therefore, the answer is B) more than 5 hours but fewer than or equal to 10 hours.

Table J.12 Consider the Following Problems in Which Six Jobs Must Each