A shell-and-tube heat exchanger is used for cooling 47 kg/s of a process stream flowing through the tubes from 160°C to 100°C. This heat exchanger has a total of 100 identical tubes, each with an inside diameter of 2.5 cm and negligible wall thickness. The average properties of the process stream are ρ = 950 kg/m³, k = 0.50 W/m·K, c_p = 3.5 kJ/kg·K and m = 2.0 mPa·s. The coolant stream is water (c_p = 4.18 kJ/kg·K) at a flow rate of 66 kg/s and an inlet temperature of 10°C, which yields an average shellside heat transfer coefficient of 4.0 kW/m²·K. Calculate the tube length if the heat exchanger has

(a) A one-shell pass and a one-tube pass

(b) A one-shell pass and four-tube passes.