Production and expenditure approaches to GDP: Consider three firms: firm A, a mining enterprise; firm B, a steelmaker; firm C, a car maker. Calculate the GDP of this economy by the product and the expenditure approach, based on the following assumptions: All values are in euros. Firm A extracts 10 million euros' worth of core. Firm B produces steel sheet worth 25 million, having bought and used all the core produced by firm A. Firm C has manufactured 75 million euros' worth of vehicles and sold them all to households, having purchased steel sheets for 20 million from firm B. In addition, Firm C imported engines from abroad for 20 million's euro, and purchased 10 million worth of robots also from abroad.