问题
单项选择题
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
答案
参考答案：B
解析：
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.