A double$-$pipe parallel$-$flow heat exchanger is used to heat cold tap water with hot water at $71\backslash$deg C$.$ The cold water enters the heat exchanger at $24\backslash$deg C at the flow rate of $0\mathrm{.}25$ kg$/$s and leaves at $47\backslash$deg C$.$ The hot water outlet temperature is recorded at $63\backslash$deg C$.$ The surface area of the heat exchanger is $3$ m$-.$ Assuming the heat exchanger is fully insulated, calculate the overall heat transtercoefficient in W$/$m$2$K$.$ The specific heat of cold water is given to be $4\mathrm{.}18$ kJ$/$kg Write your answer to two decimal places.