Water is entering a storage tank at a temperature T0 and flow rate Q0 and leaving at a flow rate Q and temperature T. There are negligible heat losses in the tank. The area of cross-section of the tank is A0. The model that describes the dynamic variation of temperature of water in the tank with time is given as :

• Q0(T0 - T) = Ac .
• Q0T0 - QT = Ac .
• Q(T0 - T) = Ac .
• Q(T0 - T) = Ac .