1. **State the problem:** We need to find the equilibrium prices $P_A$ and $P_B$ and quantities $Q_A$ and $Q_B$ where demand equals supply for both products A and B.
2. **Write down the given functions:**
Demand:
$$Q_A^d = 40 - 2P_A + P_B$$
$$Q_B^d = 300 - P_B + P_A$$
Supply:
$$Q_A^s = 10 + P_A$$
$$Q_B^s = 5 + 2P_B$$
3. **Equilibrium condition:** At equilibrium, quantity demanded equals quantity supplied for each product:
$$Q_A^d = Q_A^s$$
$$Q_B^d = Q_B^s$$
4. **Set up the system of equations:**
$$40 - 2P_A + P_B = 10 + P_A$$
$$300 - P_B + P_A = 5 + 2P_B$$
5. **Simplify each equation:**
For product A:
$$40 - 2P_A + P_B = 10 + P_A \implies 40 - 10 + P_B = 2P_A + P_A \implies 30 + P_B = 3P_A$$
Rearranged:
$$3P_A - P_B = 30$$
For product B:
$$300 - P_B + P_A = 5 + 2P_B \implies 300 - 5 + P_A = 2P_B + P_B \implies 295 + P_A = 3P_B$$
Rearranged:
$$P_A - 3P_B = -295$$
6. **Solve the system:**
From the first equation:
$$3P_A - P_B = 30 \implies P_B = 3P_A - 30$$
Substitute into the second:
$$P_A - 3(3P_A - 30) = -295$$
$$P_A - 9P_A + 90 = -295$$
$$-8P_A = -385$$
$$P_A = \frac{385}{8} = 48.125$$
Find $P_B$:
$$P_B = 3(48.125) - 30 = 144.375 - 30 = 114.375$$
7. **Find equilibrium quantities:**
$$Q_A = Q_A^s = 10 + P_A = 10 + 48.125 = 58.125$$
$$Q_B = Q_B^s = 5 + 2P_B = 5 + 2(114.375) = 5 + 228.75 = 233.75$$
**Final answer:**
$$P_A = 48.125, \quad Q_A = 58.125$$
$$P_B = 114.375, \quad Q_B = 233.75$$
Equilibrium Prices Ba52De
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