What was an important role of the parthians in the silk road trade

In a small, closed economy, national income (gdp) is $350 million for the current year. individuals have spent $100 million on the consumption of goods and services. they have paid a total of $60 million in taxes and the government has spent $75 million on goods and services this year. use this information and the national income identity to answer the questions. how much does the economy spend on investment?