pls help me with this Ex3. Thank you

Exercise 2 (7 1. Calculate the Erlang loads on a system for the following cases: /20) (a) An average call lasts 200 seconds; there are 100 call attempts per hour. (b) There are 200 mobile users in a particular cell. Each user makes a call attempt every 10 minutes, on the average. Each call lasts an average of 2 minutes 2 Consider a mobile system supporting 100 channels per cell. A call blocking probability of 1% is desired. Each user makes a call attempt every 10 minutes on the average. Each call lasts an average of 2 minutes. Say the system is concentrated in an urban area with a density of 500 cell phones per km2 Calculate the required cell radius if a hexagonal topology is assumed