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1) Suppose that the demand and supply curves for a product are the following equations:

Qs=2P (Supply); QD =90−3P (Demand).
a) Compute the equilibrium price and quantity exchanged in this market.
b) Calculate the total revenue for the suppliers at the market equilibrium
c) Compute the net social surplus at the equilibrium.

2) Now suppose that the supply curve shift to Qs =2(P−15)=2P−30.
a) Draw the new and original (from Question 1) supply curves on the same set of axes and measure the amount of horizontal shift in supply. Measure also the amount of vertical shift in supply.
b) Compute the new market equilibrium price and quantity exchanged in this market.
c) Compare your answers to in part (b) to those in Question 1(a). Explain why the magnitude of the difference in price is less than 15.

1 Answer

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Final answer:

The equilibrium price in this market is $18 and the equilibrium quantity exchanged is 36 units. The total revenue for the suppliers at the market equilibrium is $648. The net social surplus at the equilibrium is $324.

Step-by-step explanation:

To find the equilibrium price and quantity exchanged in the market, we need to set the demand equation equal to the supply equation:

Qs = QD

2P = 90 - 3P

5P = 90

P = 18

Substituting the equilibrium price back into either the demand or supply equation, we can find the equilibrium quantity:

Qs = 2(18)

Qs = 36

The equilibrium price in this market is $18 and the equilibrium quantity exchanged is 36 units.

For part b, the total revenue for the suppliers at the market equilibrium can be calculated by multiplying the equilibrium price by the equilibrium quantity:

Total Revenue = Price x Quantity

Total Revenue = 18 x 36

Total Revenue = $648

For part c, the net social surplus at the equilibrium can be calculated by finding the area between the demand and supply curves. In this case, the net social surplus is the triangle formed by the equilibrium price and quantity:

Net Social Surplus = 0.5 x (18) x (36)

Net Social Surplus = 0.5 x 18 x 36

Net Social Surplus = $324

For part 2a, to measure the horizontal shift in supply, we can compare the original and new supply curves. The original supply curve, Qs = 2P, starts at the vertical intercept of -0.4 and has a slope of 0.2. The new supply curve, Qs = 2(P - 15), starts at the vertical intercept of -0.4 and has a slope of 0.2 as well. The horizontal shift in supply is 15. The vertical shift in supply is -30, as shown by the difference in the vertical intercepts.

For part 2b, we can use the new supply curve, Qs = 2(P - 15), and set it equal to the demand equation, QD = 90 - 3P, to find the new equilibrium price and quantity:

2(P - 15) = 90 - 3P

5P = 120

P = 24

Substituting the new equilibrium price back into either the demand or supply equation, we can find the new equilibrium quantity:

Qs = 2(24 - 15)

Qs = 18

The new market equilibrium price is $24 and the new quantity exchanged is 18 units.

For part 2c, when comparing the new equilibrium price and quantity to the original equilibrium, we can see that the new price is higher and the new quantity is lower. The magnitude of the difference in price is less than 15 because the supply curve experienced a horizontal shift, meaning that even though the price increased, it didn't increase by the full amount of the shift because the demand and supply curves intersect at a lower price and quantity.

User Thanya
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