Supply and Demand

The quantity supplied of a good is the amount of product that a company is willing to make available for sale at a given price. The quantity demanded of a good is the amount of product that a consumer is  willing to purchase at a given price. Suppose that the quantity supplied S, and quantity demanded, D, of a cellular telephones each month are given by the following functions

S(p)=60p900S ;


  1. The equilibrium price of a product is defined as the quantity supplied is equal to quantity demanded. That is, the price at which S(p)=D(p)S(p)=D(p). Find the equilibrium price of cellular phone. What is the equilibrium quantity–the amount demanded (or supplied) at the equilibrium price?
  2. Determine the price for which quantity supplied is greater than quantity demanded, that is, solve the inequality S(p)>D(p)S(p)>D(p)
  3. Graph the S=S(p)S=S(p)D=D(p)D=D(p) on graphing calculator () and label the equilibrium price (part is 3 is optional)

( Go to setting and Choose -5<x<110, and -5<y<3000 as the scale for x and y axis)