Q 8~15:

The customer support hotline for Bitway Computers is currently staffed by two technicians. Calls arrive randomly at a rate of seven per hour and follow a Poisson distribution. The technician can service calls at an average rate of ten per hour, but the actual time required to handle a given call is an exponential random variable.

What is the expected number of customers waiting for the call being answered?

a. 0.0977

b. .1523

c. .9

d. .0061

Question 9

What is the expected waiting time before a customers call being answered?

a. 0.0976 hours

b. 0.01396 hours

c. 0.11396 hours

d. 0.8 hours

Question 10

What is the expected waiting time a customer has to spend in the system?

a. 0.0976 hours

b. 0.01396 hours

c. 0.11396 hours

d. 0.8 hours

Question 11

What is the expected number of customers in the system?

a. 0.5320

b. 0.6679

c. 0.9190

d. 0.7977

Question 12

What is the percentage of the time the server is busy?

a. 70%

b. 60%

c. 40%

d. 35%

Question 13

What is the probability that there is no customer in the system?

a. 45.11%

b. 48.15%

c. 33.33%

d. 35%

Question 14

What is the probability that a customer has to wait before his call was answered?

a. 20.27%

b. 35.31%

c. 70.22%

d. 18.15%

Question 15

If the wage is $10hour, waiting time cost is $5/hour, and service time cost is $2/hours, what is the total hourly cost?

a. $21.8886

b. $11.8886

c. $20

d. $15