A large office complex has a paper shredding center. Stacks of documents arrive according

to an Expo$(5)$ second inter$-$arrival time. There are three shredders and all operate

independently, each with its own queue of jobs $($stacks of documents$)$ to be processed.

When a job first arrives at the center an operator decides which shredder to send the job to$.$

Shredders #$1$ and #$2$ are considered the "main" shredders.

When a job $($stack of documents to shred$)$ arrives it will be assigned to the main shredder

with the fewest number of jobs waiting to be processed. If both of the main shredders have

the same number of jobs waiting, then the shredder choice is as follows $($essentially a "flip$-$

flop" rule$)$:

if the last job sent to a main shredder was sent to Shredder #$1,$ then the current job is

sent to Shredder #$2$;

if the last job sent to a main shredder was sent to Shredder #$2,$ then the current job is

sent to Shredder #$1.$

However, if the sum of the jobs $($i$.$e$.$ total number$)$ waiting to be processed on the main

shredders is nine $(9)$ or greater, the job is sent to the "overflow" shredder $($Shredder #$3,$ an

older and slower shredder$)$ instead.

Shredders #$1$ and #$2$ take TRIA $(9,12,15)$ seconds to shred a document while Shredder #$3$

takes TRIA $(17,19,22).$

We are interested in the queuing statistics $($length of line, waiting time$)$ for each of the

shredders, shredder utilization, as well as the waiting and total time through the system for

a job $($stack of docs$).$ Could we improve the system by changing the queue level at which

the overflow shredder is used $($the "overflow threshold"$)?$

Please build an Arena model that represents the shredding center operation over an $8$ hour

business day and experiment with different threshold values.

Hints: think about using the NQ or NR functions with Decide modules to route the jobs $($or

if a PickQ or QPick block might be useful here$).$ Using a variable to track which shredder

was the last one assigned may be something to think about as well.

$***$Im having issues setting up this arena model I have completed it twice and have still ran into errors hoping for some clarification and some help how the model should look and run