Q1. Suppose that the demand curve for soybeans shifts such that the equilibrium price of soybeans decreases 58%. At the new equilibrium price, the quantity that soybean suppliers are willing to provide decreases by 3%. Which of the following most accurately describes the respective elasticity of supply and relative elasticity for soybeans?

A)   +0.05; inelastic.

B)   +19.33; inelastic.

C)   −0.05; elastic.

Q2. Which of the following most accurately describes elasticity of supply? Elasticity of supply is the percentage change in the quantity supplied divided by the percentage change in:

A)   price and it equals zero when supply is perfectly inelastic.

B)   price and it equals zero when supply is perfectly elastic.

C)   quantity demanded and it equals infinity when supply is perfectly inelastic.

Q3. Suppose that the demand curve for honey shifts such that the equilibrium price for a pound of honey increases from $7 to $9 per pound. At the new equilibrium, the quantity supplied increases from 500 pounds per month to 600 pounds per month, although the supply curve has not shifted. The elasticity of supply for honey is closest to:

A)   +0.91.

B)   +1.12.

C)   +0.73.

[此贴子已经被作者于2008-12-31 9:31:47编辑过]

答案和详解如下：

Q1. Suppose that the demand curve for soybeans shifts such that the equilibrium price of soybeans decreases 58%. At the new equilibrium price, the quantity that soybean suppliers are willing to provide decreases by 3%. Which of the following most accurately describes the respective elasticity of supply and relative elasticity for soybeans?

A)   +0.05; inelastic.

B)   +19.33; inelastic.

C)   −0.05; elastic.

Correct answer is A)

A perfectly inelastic supply curve is vertical (elasticity = 0). In this case, the elasticity of supply is close to zero. Therefore the supply of soybeans is relatively inelastic.

Q2. Which of the following most accurately describes elasticity of supply? Elasticity of supply is the percentage change in the quantity supplied divided by the percentage change in:

A)   price and it equals zero when supply is perfectly inelastic.

B)   price and it equals zero when supply is perfectly elastic.

C)   quantity demanded and it equals infinity when supply is perfectly inelastic.

Correct answer is A)

Elasticity of supply equals zero when the supply curve is vertical, indicating perfectly inelastic supply.

Q3. Suppose that the demand curve for honey shifts such that the equilibrium price for a pound of honey increases from $7 to $9 per pound. At the new equilibrium, the quantity supplied increases from 500 pounds per month to 600 pounds per month, although the supply curve has not shifted. The elasticity of supply for honey is closest to:

A)   +0.91.

B)   +1.12.

C)   +0.73.

Correct answer is C)

The average quantity of honey supplied is (500 + 600) / 2 = 550 pounds, and the average price of honey ($7 + $9) / 2 = $8 per pound. So, the percentage change in quantity is (600 – 500) / 550 = 18.18% and the percentage change in price is (9 - 7) / 8 = 25.00%. Thus, the elasticity of supply is 18.18 / 25.00 = +0.73.

谢谢楼主～

谢谢楼主

O(∩_∩)O谢谢

Thx

THX