Price Ceiling/Floor

Price Ceiling

价格上限在 $P-Q$ 图像上表示为一条水平线

Ceiling Line

• 黑色实线为坐标轴，纵轴 $P$，横轴为 $Q$
• 橙色线表示 $P=F(Q^s)$
• 黄色线表示 $P=F(Q^d)$
• 蓝色线表示 Price Ceiling，

于是此时我们可以看到，需求量远远大于供给量，于是在供给量固定的情况下，市场上的买家需要争夺这些稀缺的供给……我们来看四种情况

Bribery

第一种解决办法，加价/拍卖。Total Value of bribery 会计入 Surplus 中

Waiting in Line

Total Value of Time，会算作损失

例题

2024 Summer

Suppose the demand and supply of Cannabis in Neverland community are given as follows:

• Demand: $P = 930 - 589Q$
• Supply: $P = 180 + 2.5Q$

In which $P$ is the price per kg in thousand dollars and $Q$ is the quantity in thousand kgs.
Note:
$1 \text{ thousand} \times (1 \text{ thousand}) = 1 \text{ million}$

18. The unregulated equilibrium Cannabis price is [ Answer18A ] thousand dollars per kg and the equilibrium quantity is [ Answer18B ] thousand kgs.

19. Suppose the government purchases $10$ thousand kgs of Cannabis back from the market regardless of price. After the government enters the market, on the new market demand curve, when the price is $555$ thousand dollars per kg, the total quantity demanded is [ Answer19 ] thousand kgs.

20. Suppose the government wants to use a buyback program to reduce the quantity of Cannabis traded in the community to zero. The government will need to buy at least [ Answer20A ] thousand kgs from the market and spend at least [ Answer20B ] million dollars.

21. Suppose the government wants to use a price floor to reduce the quantity of Cannabis traded in the community to zero. The government will need to implement a price floor of [ Answer21A ] (A. at most; B. at least) [ Answer21B ] thousand dollars per kg.

22. Knowing that the government is determined to reduce the quantity of Cannabis traded in the community to zero through either buyback or price floor, the Cannabis suppliers are actively thinking of lobbying the government for a policy they favor. The Cannabis suppliers as a group are willing to spend up to [ Answer22 ] million dollars to lobby the government to adopt the policy they favor.