9) A classical economy is described by the following equations:
Cd = 500 + 0.5(Y – T) – 100r.
Id = 350 – 100r.
L = 0.5Y – 200i.
= 1850.
πe = 0.05.
Government spending and taxes are equal where T = G = 200. The nominal money supply M =
3560.
(a) What are the equilibrium values of the real interest rate, the price level, consumption, and
investment?
(b) Suppose an economic shock increases desired investment by 10, so it is now Id = 360 – 100r.
How does this affect the equilibrium values of the real interest rate, the price level, consumption,
and investment?
(c) Returning to the initial situation in part (a), suppose an economic shock increases desired
consumption by 10, so it is now Cd = 510 + 0.5 (Y – T) – 100r. How does this affect the
equilibrium values of the real interest rate, the price level, consumption, and investment?
10) Suppose the money demand of individuals and firms depends on what they perceive to be the
probabilities that the economy will expand or contract over the following six months. Suppose
their money demand is given by the equation L = 0.5Y – 100i + 20z, where z is the probability
that the economy is expanding six months in the future. If z = 1, the economy will certainly be in
recovery, if z = 0, the economy will certainly be in recession, and for z between 0 and 1 there is
some uncertainty about the future state of the economy. Use a classical (RBC) model of the
economy. If the Fed moves the money supply to target the price level, how does the money
supply relate to the expected future state of the economy? Is this an example of reverse
causation?