Determine the overall heat transfer coefficient $U_0$ based on outer

surface of a $2\mathrm{.}54$ cm O$.$D$,2\mathrm{.}286$ cm I.D$.$ heat exchanger tube

$\frac{W}{m}.k),$ if the heat transfer coefficients at the inner and outer tubes are

$h_i=5500\frac{W}{m^2}.k$ and $h_o=3800\frac{W}{m^2}.k$ respectively and fouling factors

are $R_{fi}=R_{fo}=0\mathrm{.}0002m^2\frac{k}{W}.$