Below are arrival and service times of four single-server queues. (Hint: Mean arrrival time of 4 and mean service time of 3 are the same across all the queues, but their ranges are different.) (Queue W) Customer: 1 2 4 5 8 Mean Arrival times (hrs): 3 4 3 5 5 5 Service times (hrs): 1 4 5 2 1 3 P 100 w WIN и NN 4 4 NI Ne
(Queue X) Customer Arrival times (hrs): Service times (hrs): 1 3 2 3 3 4 5 5 4 6 5 3 7 4 2 8 Mean 5 4 3 3 4 4
(Queue Y) Customer: Arrival times (hrs); Service times (hrs): 1 4 3 2 7 mim 4 5 2 5 1 4 6 2 NN 8 Mean 6 4 2 3 4 4
(Queue Z) Customer: Arrival times (hrs): Service times (hrs): 1 4 1 2 7 5 3 3 4 4 5 2 5 1 4 6 2 5 8 Mean 6 4 1 3 3
5. (American Vending) Use the posted queueing template. For one repair worker, the average flow time (W) is For two repair workers, the average flow time (W) is For three repair workers, the average flow time (W) is
A. 0.4, 0.204, 0.225
B. 0.5, 0.204, 0.225
C. 0.4, 0.225, 0.204
D. 0.5, 0.225, 0.204
E. 0.4, 0.304, 0.325
F. 0.5, 0.304, 0.325
G. 0.4, 0.325, 0.304
H. 0.5, 0.325, 0.304
6. (American Vending) Use the Little's law to find average down machines in the entire system (L). (Note: To avoid rounding errors, use exactly the same average flow time (W) in the previous question.) -- For one repair worker, average down machines in the entire system (L) are For two repair workers, average down machines in the entire system (L) are For three repair workers, average down machines in the entire system (L) are
A. 1.5, 0.61, 0.68
B. 2.5, 0.61, 0.68
C. 1.5, 0.68, 0.61
D. 2.5, 0.68, 0.61
E. 1.5, 0.71, 0.78
F. 2.5, 0.71, 0.78
G. 1.5, 0.78, 0.71
H. 2.5, 0.78, 0.71 7.
(American Vending) Each repair worker is paid $4 per hour and downtime costs the company $25 per hour per machine. Calculate total cost (= worker cost + downtime cost). (Note: To avoid rounding errors, use exactly the same average number of down machines (L) in the previous question.) --- For one repair worker, total cost is -- For two repair workers, total cost is --- For three repair workers, total cost is
A. 21.5, 15, 17.25
B. 41.5, 15, 17.25
C. 21.5, 17.25, 15
D. 41.5, 17.25, 15
E. 21.5, 25, 27.25
F. 41.5, 25, 27.25
G. 21.5, 27.25, 25
H. 41.5, 27.25, 25
8. (American Vending) The optimal crew size is
A. 1 E 5
B. 2 F. 6
C. 3 G. 7
D. 4 H. 8