Answer and Explanation:
The computation is shown below:
Marginal Propensity to Consume (MPC) = change in consumption change in disposable income
= $18 billion ÷ $20 billion
= 0.9
Marginal Propensity to Save (MPS) = change in saving ÷ change in disposable income
= $2 billion ÷ $20 billion
= 0.10
b) APC before the increase in disposable income
The average propensity to consume (APC) = Consumption (C) ÷ Disposable income (Y)
= $150 billion ÷ $200 billion
= 0.75
For After the increase in the disposable income, first we have to determine the new disposable income and the new consumption which is
New disposable income is
= $200 billion + $20 billion
= $220 billion
And,
New consumption is
= $150 billion + $18 billion
= $168 billion
Now
APC = new consumption ÷new disposable income
= $168 billion ÷ $220 billion
= 0.76
We simply applied the above formulas