A 200-g copper calorimeter can contains 150 g of oil at 20 °C. To the oil is added 80 g of aluminum at 300 °C. What will be the temperature of the system after equilibrium is established? c_Cu = 0.093 cal/g·°C, c_Al = 0.21 cal/g·°C, c_oil = 0.37 cal/g·°C.