Answer:
In a closed economy,
GDP = Y = C + I + G
where,
C = Consumption of households on goods and service
I = investment
G = government expenditure on goods and services
Macroeconomic households generally used their personal disposable income (after tax income) to consume and save.
Therefore, GDP is either consumed by the individuals, invested by the companies or purchases by the government.
We make an assumption that households utilize their disposable income to consume and save.
Therefore, C + I + G = C + S + T
Hence,
GDP = Y = C + I + G
$500 million = $300 million + I + $150 million
I = 500 - 300 - 150
= $50.
(1) $50 million spend on investment.
(2) I = S
Hence, National savings = $50
(3) Option (a) is correct.
In this economy, National savings is equal to investment.