A person makes a quantity of iced tea by mixing 500 g of hot tea (essentially water) with an equal mass of ice at its melting point. Assume that mixture has negligible energy exchange with environment. If tea's initial temperature is Ti = 90 C, when thermal equilibrium is reached what are (a) the mixture's temperature T final and (b) the remaining mass m final of ice? If Ti = 70 C, when the thermal equilibrium is reached what are (c) T final and (d) m final?