Gubser Welding, Inc., operates a welding service for construction and automotive repair jobs. Assume that the arrival of jobs at the company's office can be described by a Poisson probability distribution with an arrival rate of two jobs per 8-hour day. The time required to complete the jobs follows a normal probability distribution with a mean time of 3.2 hours per job and a standard deviation of 2 hours. Answer the following questions, assuming that Gubser uses one welder to complete jobs.

1. What is the average number of jobs waiting for service?

a. 89/10

b. 4/5

c. 121/10

d. 89/40

2. What is the average time a job waits before the welder can begin working on it?

a. 89/10

b. 4/5

c. 121/10

d. 89/40

3. What is the average number of hours between when a job is received and when it is completed?

a. 89/10

b. 4/5

c. 121/10

d. 89/40

4. What percentage of the time is Gubser's welder busy?

a. 89/10

b. 4/5

c. 121/10

d. 89/40