1.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)   +0.73.

C)   +1.12.

D)   +0.58.

2.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 elastic.

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

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

D)   quantity demanded and it equals unity when supply is perfectly elastic.

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

A)                                        -0.05      Elastic

B)                                        +0.05     Inelastic

C)                                        +19.33   Inelastic

D)                                        -19.33    Elastic

答案和详解如下：

1.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)   +0.73.

C)   +1.12.

D)   +0.58.

The correct answer was B)

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.

2.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 elastic.

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

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

D)   quantity demanded and it equals unity when supply is perfectly elastic.

The correct answer was B)

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

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

Elasticity of supply

Relative elasticity

A)                                        -0.05      Elastic

B)                                        +0.05     Inelastic

C)                                        +19.33   Inelastic

D)                                        -19.33    Elastic

The correct answer was B)

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.