Problem: In the market for e-readers, at the prices of $40, $60, $80, $100, and $120, the following quantities are demanded: 2000, 1600, 1200, 800, and 600 units. The quantities supplied at those prices are 400, 800, 1200, 1600, and 2000 units. Draw a graph of this market. For the 800th unit, what is the consumer surplus? What is the producer surplus?