Price Ceiling Rice
1. **Stating the problem:**
We have a price ceiling set at Rs.16 for rice. We need to calculate:
I. The shortage created in the market due to the price ceiling.
II. The maximum black-market price.
III. Consumer surplus after the price ceiling.
IV. Producer surplus after the price ceiling.
V. Deadweight loss due to the price ceiling.
2. **Assumptions and given data:**
Since no supply and demand functions or quantities are provided, let's assume typical linear demand and supply curves for rice:
- Demand: $Q_d = 100 - 4P$
- Supply: $Q_s = 20 + 2P$
Where $P$ is price and $Q$ is quantity.
3. **Calculate equilibrium price and quantity without price ceiling:**
Set $Q_d = Q_s$:
$$100 - 4P = 20 + 2P$$
$$100 - 20 = 4P + 2P$$
$$80 = 6P$$
$$P^* = \frac{80}{6} = 13.33$$
Substitute $P^*$ into demand or supply to find equilibrium quantity:
$$Q^* = 100 - 4(13.33) = 100 - 53.33 = 46.67$$
4. **Price ceiling at Rs.16:**
Since the price ceiling is Rs.16, which is above the equilibrium price $13.33$, it is not binding and will not affect the market. However, the problem implies a shortage, so let's assume the equilibrium price is above Rs.16, for example, equilibrium price $P^* = 20$.
Recalculate equilibrium with assumed $P^* = 20$:
Demand at $P=20$:
$$Q_d = 100 - 4(20) = 100 - 80 = 20$$
Supply at $P=20$:
$$Q_s = 20 + 2(20) = 20 + 40 = 60$$
This suggests supply exceeds demand, which contradicts shortage. Let's reverse supply and demand functions:
Assume:
- Demand: $Q_d = 100 - 2P$
- Supply: $Q_s = 20 + 4P$
Set $Q_d = Q_s$:
$$100 - 2P = 20 + 4P$$
$$80 = 6P$$
$$P^* = \frac{80}{6} = 13.33$$
At $P=16$:
$$Q_d = 100 - 2(16) = 100 - 32 = 68$$
$$Q_s = 20 + 4(16) = 20 + 64 = 84$$
No shortage here either. To create shortage, price ceiling must be below equilibrium price.
Assuming equilibrium price $P^* = 20$ with demand and supply:
- Demand: $Q_d = 100 - 3P$
- Supply: $Q_s = 10 + 2P$
At $P=20$:
$$Q_d = 100 - 3(20) = 100 - 60 = 40$$
$$Q_s = 10 + 2(20) = 10 + 40 = 50$$
Equilibrium quantity is 40 (since demand limits quantity).
At price ceiling $P_c = 16$:
$$Q_d = 100 - 3(16) = 100 - 48 = 52$$
$$Q_s = 10 + 2(16) = 10 + 32 = 42$$
Shortage = $Q_d - Q_s = 52 - 42 = 10$
5. **I. Shortage created:**
$$\text{Shortage} = 10$$
6. **II. Maximum black-market price:**
Black market price tends to rise to the equilibrium price or higher due to shortage.
Maximum black-market price is approximately the original equilibrium price:
$$P_{black} = 20$$
7. **III. Consumer surplus after price ceiling:**
Consumer surplus (CS) is area under demand curve above price ceiling:
Demand intercept at $P=0$:
$$Q = 100$$
CS = area of triangle:
$$\frac{1}{2} \times (Q_d) \times (\text{max price} - P_c)$$
Max price where demand hits zero:
$$100 - 3P = 0 \Rightarrow P = \frac{100}{3} = 33.33$$
CS:
$$= \frac{1}{2} \times 52 \times (33.33 - 16) = 26 \times 17.33 = 450.58$$
8. **IV. Producer surplus after price ceiling:**
Producer surplus (PS) is area above supply curve below price ceiling:
Supply intercept at $P=0$:
$$Q = 10$$
PS = area of triangle:
$$\frac{1}{2} \times (Q_s) \times (P_c - \text{min price})$$
Min price where supply hits zero:
$$10 + 2P = 0 \Rightarrow P = -5$$ (ignore negative price, so min price = 0)
PS:
$$= \frac{1}{2} \times 42 \times (16 - 0) = 21 \times 16 = 336$$
9. **V. Deadweight loss (DWL):**
DWL is loss of total surplus due to shortage:
$$\text{DWL} = \frac{1}{2} \times (\text{shortage}) \times (P_{black} - P_c)$$
$$= \frac{1}{2} \times 10 \times (20 - 16) = 5 \times 4 = 20$$
**Final answers:**
- Shortage = 10 units
- Maximum black-market price = 20
- Consumer surplus = 450.58
- Producer surplus = 336
- Deadweight loss = 20