FMIS 3301 QUIZ 4 1. A single vending machine serves incoming customers. The time between arrivals (T a ) is 2 minutes with standard deviation of 4 minutes, and the machine can process 120 transactions per hour at a constant rate. What is the mean time in seconds that a customer spends in the queue? * a. 20 b. 50 c. 80 d. 0.333 e. 12 T p = 30s R a = 30/hr U=30/120 = 0.25 T w = 30*(0.25/0.75)*(2) = 20s 2. What would be the mean time in the queue if the single machine is replaced with two machines which can process 60/hour each? a. 0.18 hours *b. 11 sec c. 3 min d. 71 sec e. 1 min. T p = 60s R a = 30/hr U=30/120 = 0.25 T w = 30*(0.25 1.449 /0.75)*(2) = 30*0.179*2=10.7s 3. At a process, the average processing time is 35 seconds, with a standard deviation of 14 seconds. What is the coefficient of variation of processing time? a. 0.67 b. 2.5 c. 0.16 *d. 0.4 (14/35) e. Not enough data 4. OnCall Music receives orders by: 1- mail, 2-telephone, 3-internet site, and 4- e-mail. The hourly
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