A milling department has 10 machines. Each operates an average of eight hours before requiring adjustment, which takes an average of 2.00 hours. While running, each machine can produce 37 pieces an hour. Use Table Table 1, Table 2 and Table 3. a. With one adjuster, what is the net average hourly output per machine? (Round your answer to 1 decimal place.) Number of pieces per machine b. If machine downtime cost is $62 per hour and adjuster cost is $28 per hour, how many adjusters would be optimal?

• 1

• 2

• 3

• 4

• 5

One operator services a bank of five machines. Machine running time and service time are both exponential. Machines run for an average of 95 minutes between service requirements, and service time averages 30 minutes. The operator receives $20 per hour in salary and fringe benefits, and machine downtime costs $74 per hour per machine. Use Table 1, Table 2 and Table 3. a. If each machine produces 50 pieces per hour while running, find the average hourly output of each machine, when waiting and service times are taken into account.(Round your answer to 2 decimal places.) Average hourly output pieces b. Determine the optimum number of operators.

• 2 operators

• 3 operators

• 4 operators

The following information pertains to telephone calls to a motel switchboard on a typical Tuesday. Use Table 1.

Period	Incoming Rate (calls per minute)		Service Rate (calls per minute per operator)		Number of Operators
Morning	1.8		1.5		2
Afternoon	2.7		1.0		3
Evening	1.6		.5		4

a. Determine the average time callers wait to have their calls answered for each period and the probability that a caller will have to wait for each period. (Round intermediate calculations and final answers to 3 decimal places.)

Period	Pw
Morning
Afternoon
Evening

b. Determine the maximum line length for a probability of 98 percent. (Round your intermediate calculations to 3 decimal places and round up your final answers to the next whole number.)

Period	Lmax
Morning
Afternoon
Evening

Trucks arrive at the loading dock of a wholesale grocer at the rate of 1.2 per hour. A single crew consisting of two workers can load a truck in about 30 minutes. Crew members receive $10 per hour in wages and fringe benefits, and trucks and drivers reflect an hourly cost of $61. The manager is thinking of adding another member to the crew. The service rate would then be 2.4 trucks per hour. Assume rates are Poisson. . Use Table 1 and Table 2. a. Would the third crew member be economical? (Round your intermediate and final answer to 2 decimal places. Omit the "$" sign in your response.) (Click to select) Yes No because, the total cost is $ . b. Would a fourth member be justifiable if the resulting service capacity were 3 trucks per hour? (Round your intermediate and final answer to 2 decimal places. Omit the "$" sign in your response.) (Click to select) Yes No because, the total cost is $ .

One field representative services 5 customers for a computer manufacturer. Customers request assistance at an average (Poisson-distributed) rate of once every 2.8 working days. The field representative can handle an average (Poisson-distributed) of 1.0 call per day. Determine: Use Table 1. a. The expected number of customers waiting. (Round "X" value to 2 decimal places. Round your answer to 3 decimal places.) Expected number of customers waiting b. The average length of time customers must wait from the initial request for service until the service has been completed. (Round your answer to 2 decimal places.) Average length of time days c. The percentage of time the service rep will be idle. (Round your answer to 1 decimal place.) Percentage of Idle time d. By how much would your answer to part a be reduced if a second field rep were added? (Round your answer to 3 decimal places.) Reduced number of customer(s)