melude both

Nir passing through am is $$3\mathrm{.}70$ per nillion ki$,$

ca to a side by $30$ ang long at a a ease langular cross section duct

to be herated fira $27C$ Long at a rase plowete of $57C.$ vapoar is cometensing ${00}^{-3}k\frac{g}{s}$ is

suriace of the duat so that the toreperature is ofing on the outer

assumed to be invariant, Deternine the the tompere of the duct tay be

vill result In the alr belng heated in the nature of the auct that

an curowated Devar versel comerised maner desorthed above.

sipecteal stalmiess steel sholls coperised of thin

are $610$ oxyen at $90$ R $,$ the ont