Benzene and Toluene at 1 atm absolute pressure and 70 C needs to be cooled to 45 C. The flow rate of the mixed aromatic stream is 50 kg per minute. The composition of the stream can range from 15 wt% benzene to 55 wt% benzene, with the balance being toluene. The mixed aromatic stream will be cooled using a heat exchanger. The utility stream is liquid water at 35 C that leaves the heat exchanger at 40 C. Find the utility demand for the range of expected compositions of the mixed aromatic stream.

Assume that the heat capacity depends linearly on temperature (Cp = a + bT)