In 1987, a company called Burroughs-Wellcome introduced its anti-AIDS drug AZT and an introductory price of $12,000 annually. Suppose the marginal cost of producing an annual dosage of the drug was $100 and that $12,000 was the optimal price. What is effect on the number of annual doses sold of a 10% increase in the price of the drug? Explain how you obtain your answer, showing all calculations.