If real GDP is $30 trillion, explain the process that takes the economy to equilibrium expenditure. If real GDP is $40 trillion, explain the process that takes the economy to equilibrium expenditure.

In an economy with no exports and no imports, autonomous consumption is $1 trillion, the marginal propensity to consume is 0.8, investment is $5 trillion, and government expenditure on goods and services is $4 trillion. Taxes are $4 trillion and do not vary with real GDP.