A study of U.S. colleges and universities resulted in the demand equation q=20,000 -2p. where q is the enrollment at a public college or university and p is the average annual tuition (plus fees) it charges. Officials at Enormous State University have developed a policy whereby the number of students it will accept per year at a tuition level of p dollars is given by q = 7,500+ 0.5p. Find the equilibrium tuition price p and the consumers' and producers' surpluses at this tuition level. What is the total social gain at the equilibrium price?