Consider five firms in the closed economy: a steel producer, rubber producer, machine tool maker, tyre producer, and bicycle manufacturer. The bicycle manufacturer sells bicycles produced to final customers for $8000. In producing the bicycles, the firm buys tyres ($1000), steel ($2500), and machine tools ($1800). The tyre manufacturer buys rubber ($600) from rubber producer and machine tool maker buys steel ($1000) from the steel producer. Identify final and intermediate goods for the economy.

(a) Calculate the value of total sales; the value added by each firm and the total value added; the value of intermediate product of each firm and the value of total intermediate product; the total final expenditure, the value of GDP.