Consider the following information about an economy.

C=100+b(Y-50-0.25Y);

I=50,

G=50,

X=10,

M=5+0.1y,

t=0.25Y,

MPC=0.8

1. Find equilibrium national income
2. Find the foreign trade multiplier
3. What components are excluded in calculating national income and why?
4. What is the most common method of computing national income in Zambia and why?
5. What is the effect of an increase in t of 0.3 on the equilibrium income and the multiplier?