消费者剩余：图形解释

Consider three students from a college band. They enjoy eating muffins priced at $3 each at the cafeteria post-rehearsal.

John values a muffin at $9, so his consumer surplus is $6. 

Alex, who values it at $8, has a surplus of $5. Mary, willing to pay $7, gets a surplus of $4.

This analysis can be extended to the entire market for muffins by using the market demand curve, which shows the quantity consumers are willing to buy at a given price. 

Consumer surplus is represented by the area above the market price, which is below the demand curve and up to the quantity demanded at the market price. This area is represented by the triangle ABC.

For any product, the base of the consumer surplus triangle is the quantity sold at the market price. The height of the triangle is the difference between the demand choke price and the market price. 

The demand choke price is the price at which the quantity demanded is reduced to zero.

To summarise, consumer surplus quantifies the benefits that buyers receive by engaging in the market.