Answer:
The answer is $150 million
Explanation:
A closed economy is also called autarky. A closed economy is an economy that trades only within its economy. There is no import and there is no export also. The economy (country) is self-sufficient.
The formula for GDP in a closed economy equals C + I + G
where C is the household/individual consumption.
I is the business or firm's investment
G is the government spending.
GDP is $600million
C is $ 250 million
G is $ 200 million
I = ($600 - $ 250 - $200) million
I= $150 million