每日一练

例题

Question: Consumer surplus

A. Find Marginal Buyer’s WTP (Willingness to Pay) at Q=10.

B. Find Consumer Surplus for P=30.

Suppose P falls to $20. How much will Consumer Surplus increase due to:

C. buyers entering the market

D. existing buyers paying lower price

解析

A. At Q=10, marginal buyer’s WTP (willingness to pay) is $30.

B. Consumer surplus = ½ ×10 × $10 = $50

     P falls to $20.

C. Consumer surplus for the additional buyers = ½ ×10 × $10 = $50

D. Increase in Consumer surplus o initial 10 units = 10 × $10 = $100

下面我们为大家准备了一道同类型的题目，请大家一起来试试解答。

Question: Producer Surplus

A. Find Marginal Seller’s cost at Q=10.

B. Find total Producer Surplus for P=$20.

Suppose P rises to $30.

Find the increase in Producer Surplus due to:

C. selling 5 additional units

D. getting a higher price on the initial 10 units

（答案见下方）

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

A. At Q=10, marginal cost=$20

B. Producer surplus = ½ × 10 × $20 =$100

     P rises to $30.

C. Producer surplus on additional units = ½ × 5 × $10 = $25

D. Increase in Producer surplus on initial 10 units = 10 × $10 = $100