In: Economics
The economy is represented by the following equations:
Financial Sector:
L=(Md/P)=4Y-120i
(Ms/P)=$5,300
Real Sector:
C=$120+0.8YD
YD=Y-TA+TR
TA=0.25Y
TR=100
I=$200-18i
G=$400
Y=AD=C+I+G
a). Solve for the equilibrium level of Y and i
b). If G increases from 400 to 430, find the new equilibrium Y and I
c). Using the equilibrium values from a). and b). calculate the Crowding Out effect from expansionary fiscal policy
d). Convert both the IS and LM curves from a). into slope-intercept form
a)
IS curve is given by
Y = C + I + G
Y = 120 + 0.8YD + 200 - 18i + 400
Y = 720 + 0.8(Y - TA + TR) - 18i
Y = 720 + 0.8(Y - 0.25Y + 100) - 18i
Y = 720 + 0.8Y(0.75Y + 100) - 18i
Y = 720 + 0.6Y + 80 - 18i
Y - 0.6Y = 800 - 18i
0.4Y = 800 - 18i
Y = 2000 - 45i
Equation of IS curve is
Y = 2000 - 45i
LM curve is given by
Md/P = Ms/P
4Y - 120i = 5300
4Y = 5300 + 120i
Y = 1325 + 30i
LM curve equation is
Y = 1325 + 30i
In Equilibrium YIS = YLM
2000 - 45i = 1325 + 30i
2000 - 1325 = 30i + 45i
675 = 75i
i = 9
Y = 1325 + 30(9)
Y = 1595
Equilibrium level of income is Y = 1595 and
Equilibrium level of interest rate is i = 9
b)
Now G increases from 400 to 430
New equation of IS curve would be
Y = 120 + 0.8YD + 200 - 18i + 430
Y = 750 + 0.8(Y - TA + TR) - 18i
Y = 750 + 0.8(Y - 0.25Y + 100) - 18i
Y = 750 + 0.8Y(0.75Y + 100) - 18i
Y = 750 + 0.6Y + 80 - 18i
Y - 0.6Y = 830 - 18i
0.4Y = 830 - 18i
Y = 2075 - 45i
New equation of IS curve is
Y = 2075 - 45i
LM curve equation is
Y = 1325 + 30i
In Equilibrium YIS = YLM
2075 - 45i = 1325 + 30i
2075 - 1325 = 30i + 45i
750 = 75i
i = 10
Y = 1325 + 30(10)
Y = 1625
The new equilibrium level of Y and i are 1625 and 10 respectively.
In fact Y = 1625 is the new equilibrium value of income when there is an interest rate effect. So we call this as
Y2 = 1625
when there is no interest rate effect then equilibrium value of income is given by
Y/G = 1/(1 - c + ct)
c = 0.8
t = 0.25
Y/G = 1/(1 - 0.8 + 0.80.25)
Since G increases from 400 to 430 therefore G = 430 - 400 = 30
Y/30 = 1/0.4
Y = 30/0.4
Y = 75
New equilibrium level of income when there is no interest rate effect is Y1 = Y + Y = 1595 + 75 = 1670
c)
Crowding out effect = Y1 - Y2 = 1670 - 1625 = 45
d)
We have
IS : Y = 2000 - 45i
Y = 2000 - 45i
45i = 2000 - Y
i = 44.44 - 0.022Y
Slope intercept form of IS curve is
i = 44.44 - 0.022Y
Likewise
LM curve is
Y = 1325 + 30i
Y - 1325 = 30i
0.033Y - 44.16 = i
Slope intercept form of LM curve is
i = 0.033Y - 44.16