$$

$2.$ Dumfries Industries is generating a materials requirement plan for the next six weeks. Here is its most current information:

Master Production Schedule

Week

$1$

$2$

$3$

$4$

$5$

$6$

Item A

$10$

$0$

$20$

$20$

$10$

$10$

Other information

Item

Item$$s Parent

Lead time

Lot size

Current inventory

A

None

$1$ week

LFL

$20$

B

A

$1$ week

$20$

$20$

C

B

$1$ week

$50$

$20$

$$

a$.$ How many levels does a product structure for Dumfries item A have?

$$

b$.$ Using MRP methodology, how much of Parts A$,$ B$,$ and C should be ordered, and when should they be ordered?

$$

c$.$ Which item will experience the highest average inventory, following this plan?

$$

$$

$3.$ Consider the following three jobs: Job Alpha requires two weeks of work and is due in four weeks. Job Beta requires three weeks of work and is due in five weeks. Job Carlos requires one week of work and is due in three weeks. If these jobs are completed in alphabetical order, how late will Job Beta be$?$

$$

$$

$4.$ Suppose you have three jobs waiting to be completed, and you must determine the sequence in which these jobs should be worked on$.$ You calculated the critical ratio for each of the jobs and the results were that Job A has a critical ratio of $1\mathrm{.}27,$ Job B has a critical ratio of $-0\mathrm{.}89,$ and Job C has a critical ratio of $0\mathrm{.}15.$ Which of these jobs is already late? Why?

$$