2021年CFA考试《Level Ⅰ》考试题库-CFA考试（Level Ⅰ）-Study Session 4　Economics Microeconomic Analysis-

财会经济-CFA特许金融分析师

单选题-A demand function for cellular telephones is given by:= 390-4 + 0. 015 income + 2. 2 e-0. 55 . At current average prices, a cellphone costs $100, a landline costs $60, and wireless service costs $40. Average income is $20,000. The price of cellular telephones as a function of quantity demanded (QD) is most accuratelydescribed as:

单选题

A.400.

B.$100 QD cellphone.

C.200-0.25 QD cellphone..

我个人认为这个应该是：C

解析：Substituting current values for the independent variables other than price, the demand function becomes:
= 390－4 + 0. 015(20,000) + 2. 2(60)－0. 55(40)
= 390－4 + 300 + 132 – 22
= 800－4
Solving algebraically, we have:
= 800－4
－800 =－4 －0. 25
+200 =
= 200－0. 25