Assignment:
Question 1. A company needs to provide sufficient private trunks between two switches to accommodate 90% of call attempts among employees during the busy hour. Assume that there will be 560 callers at random times during that hour, and that call duration averages 3 minutes. Employees are instructed to attempt to call using a trunk; if blocked, callers will use a more expensive company-issued calling card. How many trunks will be needed?
Question 2. In order to eliminate the cost of calling cards, the company in the above problem is considering a new policy that requires blocked callers to redial over and over until they get a trunk. Assuming the same number of callers and the same call duration, what is the new level of blockage, and about how long is the average total call time including both dialing and talking?