Trying to find the right answer to this..

Determination of Income and Employment

Question

An economy is in equilibrium. Calculate national income from the following:
Autonomous consumption (C) = 100
Marginal propensity to save (S) = 0.2
Investment expenditure (I) = 200

Answer

Autonomous consumption (C) = 100
Marginal propensity to save (S) = 0.2
Therefore MPC (c) = 1 - MPS = 1 - 0.2 = 0.8
Investment expenditure (I) = 200
Y = C+I at equilibrium = C+_cY +I
Y=100+0.8Y+200
Y=0.8Y+300
Hence, Y-0.8Y = 300
0.2Y = 300
So, Y = 300/.2 = 1,500