Maths Part Flashcards
Your market research department has found out that the demand curve for chocolate is
Q(P) = 16 − 0.6P . The current price of chocolate is 20. What is the price elasticity of demand at this price (round to two decimals if necessary)?
Q’(P) * P/Q
El = -0.6 * (20)/(16-0.6*20)
In the perfectly competitive market for Easter eggs all producers have the same total cost function
C (q) = 108+3q2. Suppose that market demand is given by
Q(P ) = 4200−100P .
How many producers will operate in this market in the long run?
find MC, ATC => equal them:
6q = 108/q + 3q => q=6
MC=P
Find P by inverse demand fct =>
P= -Q/100 +42
36= -Q/100 +42
Q=600 ==> 600/6 = 100
A firm in a perfectly competitive market has the cost function
C (q) = 1/4 q2 + 10q.
The short-run market price is given by P = 25. How much should the firm produce in the short run?
MC = P
0.5q + 10 = 25
=> q = 30
Consider a perfectly competitive market. The demand curve is given by Q(P ) = 98 − 4P
The market supply curve is
Q(P ) = 10P
How high is the social surplus in equilibrium?
Demand:
98 - 4P => P = 24,5
Supply:
98 - 4P = 10P
98 = 14P => P = 7
Q=10P => Q= 70
24,5*70/2 = 857,5
Consider a perfectly competitive market. The demand curve is given by P (Q) = 30 − 1.5Q
and the supply curve is given by
P (Q) = 6 + 0 . 5Q.
The government introduces a tax: each consumer must pay €8 to the government for every unit the consumer buys. How high is the tax revenue?
30 - 1.5Q = 6 + 0.5Q
Q = 12
New supply curve:
P(Q)= 6 + 8 +0.5Q
==>
30 - 1,5Q = 14 + 0.5Q
Q = 8
Income government:
Q1tax => 88 = 64
Consider the perfectly competitive market for jeans in Italy. Domestic demand is Q(P ) = 1000 − 20P
and domestic supply is
Q(P ) = 20P − 200.
There is free trade. Initially, the
world market price is 35, then it drops to 20. Which of the following statements is correct?
1000 - 20P = 20P - 200
P = 30
———–
q = 20(30) - 200
q = 400
————
q = 20(35) - 200
q = 500
==> 500-400= 100 => 100*20 = 2000
A monopoly faces market demand Q(P) = 30−P
and has the cost function
C (Q) = 0.5Q2.
What is the monopolist’s profit?
Inverse demand fct: P = 30 - Q
,times by Q for revenue:
30Q - Q^2 and so MR=30-2Q
MC=Q
MR=MC => 30-2Q=Q => Q=10
we can now calculate profit:
rev-cost= (300-Q^2)-(0.5Q^2)
=> 3010-10^2 - 0.5100
=> 150
Consider a monopolist who sets the profit maximizing price. The monopolist does not have fixed costs. Marginal costs are MC = 3. The elasticity of demand at the profit
maximizing price is ELd = −2 (for your convenience I do not omit the minus sign here). What is
the profit maximizing price?
P = MC/(1-(1/ELd))
P = 3/(1-(1/-2)) = 6
The minimum wage in the U.S. was $1.50 in 1935 and $4.35 in 1998. The price index for 1935 was 34.2, and the price index for 1998 was 177.2. What is the difference between
the values of the minimum wages in terms of 1998 dollars (round to two digits)?
(1,50/34,2)*177.2 = 7.77
(4,35/177.5)*177.5 = 4.35
7.77 - 4.35 = 3.42
Consider a labor market for which the labor supply curve is given by LS (w) = 24w,
where w is the wage level. The labor demand curve is given by
LD (w) = 897 − 15w. Initially, the
market is in equilibrium. Then, there is a shock to the economy such that the labor demand changes to
LD (w) = 429−15w. The wage is downward rigid at the former equilibrium level. How
does the level of employment change?
Ls = Ld
24w = 897 - 15w
w = $23
Level of employment: 24(23) = 552
New level: 495 - 15(23) = 84
84 - 552 = - 468
Consider a monopolist with the cost function C(Q) = 4Q. Market demand is Q(P) = 48 - 2P. What is the deadweight loss from the monopoly?
Find MR, MC and D(inverse)
find the remaining values and do (b*h)/2
Consider a perfectly competitive market. Market demand is
Q(P) = 2451 - 4P.
All firms on the market are identical with cost function
C(q) = 20q^2 + 4q + 500
(q denotes the
production of the individual firm, Q is the market quantity produced by all firms together). How many firms will there be on the market in long-run equilibrium?
MC=40q + 4
ATC = 20q + 4 + 500/q
MC=ATC => q=5
P=MC => P= 40*5+4 = 204
Q=nq => Q=n5
Q= 2451 - 4204 =>
1635 => 1635=n5
n= 1635/5 => 327
The following curves are given
P(Q) = −100 Q + 12
S(P) = 300P
What is the deadweight loss occuring from a 2€ tax imposed on the buyer?
What is the income generated by the government?
Step 1 :
Inverse demand
find initial equilibrium:
1200 - 100P = 300P => P = 3
Solve Q : Q=300P => Q=900
Step 2:
Solve Q:
Q=300P => Q=3002,5 => Q=750
Step 3:
Actual new price: 2+2,5=4,5
Step 4:
DWL= 2(900-750)/2 = 150
Government Income: tax*Q = 1500
We are currently looking at a perfectly competitive
market for economics books. What is ourmaximized social surplus?
Buyers RV Sellers RV
Daniel 75 Eva 15
David 60 Erika 30
Diego 45 Elena 45
Dean 30 Elisabeth 60
Dax 15 Emily 75
Daniel and Eva = 60
David and Erika= 30
Diego and Elena = 0
==> 90
When the price of an energy drink is 1.50€, you decide to buy 8 energy drinks. When the price increases
to 2.00€ however, you decide to only buy 5 energy drinks. What is your price elasticity of demand for
energy drinks?
Price elasticity of demand =
Qnew - Qold
——————-
Qold
———————-
Price new - Price old
———————
Price old
==> -0,375/0,333 = -1,125