In: Economics
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Demand For Apples In The Wholesale Market. |
|
|
Price, P ($/lb) |
Quantity, Qd (lbs) |
|
10 |
0 |
|
8 (P1) |
4 (Q1) |
|
6 (P2) |
8 (Q2) |
|
4 (P*) |
12 (Q*) |
|
2 |
16 |
a)

b)
Qd= a+bP
a= Quantity intercept or x intercept. It is also called autonomous consumption that is quantity demanded when price is zero.
b= intercept of slope that is Change is quantity demanded divided by change in price.
Let’s find a and b,





a= Qd when price is zero, so to derive a we put value of any price (P*) and corresponding quantity demanded (Q*) in the above derived equation



The demand function : 
To derive the inverse demand function :



Inverse Demand Function :
c)
Qd=? when P=3



|
Supply For Apples In The Wholesale Market. |
|
|
Price, P ($/lb) |
Quantity, Qs (lbs) |
|
0 |
0 |
|
2 (P1) |
4 (Q1) |
|
4 (P2) |
8 (Q2) |
|
6 (P*) |
12 (Q*) |
|
8 |
16 |
(i)

(ii)
Qs= c+dP
c= Quantity intercept of supply. It is always negative because no one sells when price is zero.
d= Inverse of the slope of supply curve. It is change in quantity supplied divided by changes in prices.
To find d :





TO FIND c , WE PUT ANY VALUE OF Qs AND CORRESPONDING PRICE in above equation,
Q* = c+2P*




Supply Function :
Inverse Supply Function :


(iii) Qs=? when P= 9
Qs=2(9)
Qs=18 lbs
( I )
Market Equilibrium is when Demand (Qd) = Supply (Qs)

Qd=Qs
20-2P=2P
4P=20
P=20/4
EQUILIBRIUM PRICE= $5/lb
THEREFORE, EQUILIBRIUM QUANTITY = 2(5) = 10lbs
(II)
CONSUMER SURPLUS is the area below tha demand curve but above the equilibrium price
Consumer Surplus = Area of the double shaded triangle = 0.5x5x10 = 25
PRODUCER SURPLUS is the area above supply curve but below the equilibrium price.
Producer surplus = Area of the single shaded triangle = 0.5x5x10 = 25
TOTAL SURPLUS = Consumer Surplus+Producer Surplus
Total Surplus = 25+25 = 50

