100.
In the standard model, we expect the partial derivative of quantity supplied with respect to input price to be:
A)
positive.
B)
negative.
C)
either positive or negative.
D)
The correct answer is uncertain without more information.

101.
Suppose the demand for fabric softener can be described as
Q
D
= 1,000 –
P
+0.01
I
, where
Q
D
is the quantity of fabric softener
demanded,
P
is the price of fabric softener, and
I
is income.
Suppose that income is initially 1,000, but it falls to 800.
new
equation for the demand for fabric softener is:
The

102.
Suppose the demand for fabric softener can be described as
Q
D
= 800 –
P
–
P
D
, where
Q
D
is the quantity of fabric softener
demanded,
P
is the price of fabric softener, and
P
D
is the price of laundry detergent.
Suppose that the price of detergent is
initially 10 but increases to 15.
The
new
equation for the demand of fabric softener is:

103.
Suppose that the inverse demand curve for energy drinks can be expressed as
.
The price elasticity of demand
at a quantity of 25 is:

104.
For an elastic demand function, the derivative of the revenue function with respect to price is:
A)
positive.
B)
negative.
C)
zero.
D)
infinite.

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105.
Suppose the demand for baby shoes in a small town is described by the following equation:
Q
= 50 – 2
P
where
Q
is the quantity of baby shoes demanded and
P
is the average price of a pair of baby shoes.
a. What is the price elasticity of demand for baby shoes when the price is $15? Use calculus to show the answer.
b. What is the price elasticity of demand for baby shoes when the price is $10? Use calculus to show the answer.
106.
Suppose that the inverse demand curve for a well-known sports car can be expressed as
, where price is
in dollars and quantity is in numbers of cars.
a. What is the price elasticity of demand at a quantity of 100?
b. Is the demand for these sports cars elastic or inelastic?
107.
Suppose that the inverse demand curve for a new laptop computer can be expressed as
, where price is in
dollars and quantity is in number of laptops.
a. What is the price elasticity of demand at a quantity of 625?
b. Is the demand for these laptops elastic or inelastic?
108.
Suppose that the demand curve for a new product can be expressed as
Q
D
= 900 – 3
P.
At what price and quantity is total
expenditure maximized?
109.
Suppose that the demand curve for scissors can be expressed as
Q
D
= 600 – 0.5
P.
At what price and quantity is total
expenditure maximized?
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Answer Key