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### Section 4-14 : Business Applications

- A company can produce a maximum of 2500 widgets in a year. If they sell x widgets during the year then their profit, in dollars, is given by, \[P\left( x \right) = 500,000,000 - 1,540,000x + 1450{x^2} - \frac{1}{3}{x^3}\] How many widgets should they try to sell in order to maximize their profit?
- A company can produce a maximum of 25 widgets in a day. If they sell x widgets during the day then their profit, in dollars, is given by, \[P\left( x \right) = 3000 - 40x + 11{x^2} - \frac{1}{3}{x^3}\] How many widgets should they try to sell in order to maximize their profit?
- A management company is going to build a new apartment complex. They know that if the complex contains x apartments the maintenance costs for the building, landscaping etc. will be, \[C\left( x \right) = 70,000 + \frac{{2736}}{5}x - \frac{{211}}{{50}}{x^2} + \frac{1}{{150}}{x^3}\] The land they have purchased can hold a complex of at most 400 apartments. How many apartments should the complex have in order to minimize the maintenance costs?
- The production costs of producing x widgets is given by, \[C\left( x \right) = 2000 + 4x + \frac{{90,000}}{x}\] If the company can produce at most 200 widgets how many should they produce to minimize the production costs?
- The production costs, in dollars, per day of producing x widgets is given by, \[C\left( x \right) = 400 - 3x + 2{x^2} + 0.002{x^3}\] What is the marginal cost when \(x = 20\) and \(x = 75\)? What do your answers tell you about the production costs?
- The production costs, in dollars, per month of producing x widgets is given by, \[C\left( x \right) = 10,000 + 14x - \frac{{8,000,000}}{{{x^2}}}\] What is the marginal cost when \(x = 80\) and \(x = 150\)? What do your answers tell you about the production costs?
- The production costs, in dollars, per week of producing x widgets is given by, \[C\left( x \right) = 65,000 + 4x + 0.2{x^2} - 0.00002{x^3}\] and the demand function for the widgets is given by, \[p\left( x \right) = 5000 - 0.5x\] What is the marginal cost, marginal revenue and marginal profit when \(x = 2000\) and \(x = 4800\)? What do these numbers tell you about the cost, revenue and profit?
- The production costs, in dollars, per week of producing x widgets is given by, \[C\left( x \right) = 800 + 0.008{x^2} + \frac{{56,000}}{x}\] and the demand function for the widgets is given by, \[p\left( x \right) = 350 - 0.05x - 0.001{x^2}\] What is the marginal cost, marginal revenue and marginal profit when \(x = 175\) and \(x = 325\)? What do these numbers tell you about the cost, revenue and profit?