Practice question

Question

Milk flowing through a stainless steel inner tube ( 40 mm inner diameter) of double tube-type heater is to be heated from 10 °C to 85 °C by saturated steam condensing at 120 ° Con the outer surface of the inner tube. Total heat transferred (Q) is 146200 kcal h^-1 and the overall heat transfer coefficient is 750 kcal h^-1 m^-2 o c^-1 . The total length of the heating tube in m (rounded off to one decimal place) is