Rotelco is one of the largest digital wireless service providers in the United States. In a recent year, it had approximately 100 million direct subscribers (accounts) that generated revenue of $42,100 million. Costs and expenses for the year were as follows: Cost of revenue $18,100 Selling, general, and administrative expenses 12,200 Depreciation 4,600 Assume that 70% of the cost of revenue and 30% of the selling, general, and administrative expenses are variable to the number of direct subscribers (accounts).

a. What is Rotelco's break-even number of accounts, using the data and assumptions above?
b. How much revenue per account would be sufficient for Rotelco to break even if the number of accounts remained constant?