5. t a price of $200, a company will be able to sell 1,000 units of its product in a month. If the selling price is increased to $220, the demand will fall to 950 units. It is also known that the product has a variable cost of $140 per unit, and fixed costs will be $36,000 per month.

Required:

1. Find an equation for the demand function (that is, price as a function of quantity demanded)
2. Write down the marginal revenue function
3. Write down the marginal cost
4. Find the quantity that maximises profit
5. Calculate the optimum price