Currently the utility has fixed cost of 7000000 and marginal cost of $30. What is the profit maximization equation? 2. Originally Posted by boshbosh08 The monthly demand equation is p(x)=60-10^(-5)x where p is the price measured and x is the quanity/demand measured in kilowatt-hour. Currently the utility has fixed cost of 7000000 and marginal cost of$30.