In an air-conditioning plant, 3 kg/s of recirculated air (25 °C, specific humidity 0.010 kg/kg dry air) is mixed adiabatically with 1 kg/s of fresh air (35 °C, specific humidity 0.020 kg/kg dry air); flow rates are of dry air. Find (a) the specific humidity of the mixture (kg/kg dry air) and (b) its approximate dry-bulb temperature (°C).