A performance test is being conducted on a doublepipe counter-flow heat exchanger that carries engine oil and water at a flow rate of 2.5 kg/s and 1.75 kg/s, respectively. Since the heat exchanger has been in service over a long period of time, it is suspected that the fouling might have developed inside the heat exchanger that might have affected the overall heat transfer coefficient. The test to be carried out is such that, for a designed value of the overall heat transfer coefficient of 450 W/m²·K and a surface area of 7.5 m², the oil must be heated from 25°C to 55 °C by passing hot water at 100°C (c_p = 4206 J/kg·K) at the flow rates mentioned above. Determine if the fouling has affected the overall heat transfer coefficient. If yes, then what is the magnitude of the fouling resistance?