Hi. Having difficulty trying to understand, and keep messing up

Hi. Having difficulty trying to understand, and keep messing up big time in my calculations. I need the correct answers so I can review for the final. Can you help? Thank you.,,2. Rosenberg Manufacturing Corp. is considering marketing their new hearing aid in the city of “Big Smoke”. This device is targeted at the hearing impaired over the age of 60 years. As she considers the possibility, the VP/Marketing reviews the following data for FY 2013:,,,Retail price : $529 , Retail margin : 47.5%, Wholesale margin : 22.5%, R & D on hearing aid, FY’s 2011, 2012 : $199,000, Introductory promotional outlays, 2013 : $189,000, Manufacturing costs/unit : $99, Rosenberg’s sales commission : 5% of manufacturer’s selling price, Population of Big Smoke” : 2,500,000, Proportion of population over 60 : 17.5%, ,a) What is Rosenberg’s,i) unit contribution;,ii) contribution margin?,,b) How many units must Rosenberg sell in the first year to break even? Carefully explain, including any assumptions that you make.,,,,,c) If 20% of the “over 60” population is hearing impaired, what is Rosenberg’s break even market share in 2013? (Identify and explain any assumption(s) that are necessary). ,,,,,,,,,,,d) If Rosenberg has three competitors in the market, assess Rosenberg’s prospects of breaking even in the first year. Incorporate the market share from (b) above into your assessment. Carefully explain your reasoning.,,,,