Question $4$

$(30$ points$)$ A computer repair shop receives $2$ kinds of service jobs: repairs and upgrads. The arrival rates of repairs and upgrades are $2\mathrm{.}0$ and $1\mathrm{.}5$ per hour, respectively. The interarrival times have the exponential distribution. All arriving jobs are first being handled by technicians. When a technician completes the repair or upgrade, the computer is seat to the quality specialist for testing. Upgrades do not need any further operations and leave the shop whereas $20\%$ of all repairs fail the quality test and are sent back to the technicians. This percentage is the same no matter how many times they have been attended by a technician. After passing the quality test any repair job that has failed the quality test more than once is examined by the manager before it leaves the slop. If the repair job has not failed the quality test or failed ouly once then it leaves the job without visiting the manager. Technician time for repairs and upgrade jobs both have the triangular distribution with parameters $(10,20,40)$ and $(5,10,15)$ minutes, respectively. Quality testing time for repairs and upgrade jobs both have the uniform distribution with parameters $(8,16)$ and $(7,12)$ minutes, respectively. Manager examination time also has the uniform distribution with parameters $(10,20)$ minutes. There are $2$ technicians, $1$ quality specialist, and $1$ manager at the slop.

Tasks

Model this system in Arena.