please help explaining these questions and how to solve them

Call center "A"has an interarrival time of 3 minutes. Call center "B" has an interarrival time of 2 minutes. Round your answer to two decimal places. If the two call centers are combined into one center C (with no loss of customer demand), what will the interarrival time for call center C be (in minutes)? 1.20 minutes The interarrival time at a customer service center is 6 minutes and the average call lasts 4.8 minutes. Use Table 17A.1. Round your answer to the nearest whole number, if the center would like to keep the probability that all agents are busy less than 0.02 how many agents should the center have? 20 An airline company has 3 phone lines. Time between calls averages 4 minutes. Use Table 170.1 Report your answer as a decimal and round to 4 decimal places If an average call lasts 4.8 minutes, what is the flow rate (in calls per minute)? 1.6000 calls per minute An airline company has 4 phone lines. If the time between calls averages 3 minutes. Use Table 17A1. Round your answer to four decimal places. What is the probability that all lines are busy if an average call lasts 6 minutes? 1.5000