Water (p = 4.180 kJ/kg-K) enters a counterflow, double-pipe heat exchanger at 38C, flowing at the rate of 0.75 kg/s. It is heated by oil (p = 1.884 kJ/kg-K) flowing at the rate of 1.5 kg/s from an inlet temperature of 116C. For an area of 13.0 m2 and overall heat transfer coefficient of 340 W/m2.K, Determine the effectiveness () in %