In an oil cooler for a Diesel engine, 0.1 kg/s of oil (cp = 2131 J/kg.K) is to be cooled from 120 to 60oC in a double-pipe heat exchanger with 0.1 kg/s of cooling water (cp = 4178 J/kg.K) available at 10oC. Determine the cooling water outlet temperature and heat transfer area if the flow is counter current type. Assume U = 500 W/m2.K