CAIE-Alevel-经济学-AS分类练习+解析

What is meant by consumer surplus?

In a competitive market, the graph displays equilibrium at price P and quantity Q. Which region on the graph represents the consumer surplus and which region represents the producer surplus?

A consumer had $700 and preferred to spend the money on a new refrigerator rather than a new washing machine. When she went to the shop, she found out that the refrigerator cost $600 and the washing machine cost $500. She decided to purchase the refrigerator. What was her consumer surplus and opportunity cost?