$4\mathrm{.}5\mathrm{.}4$ If the pressure difference between points $1$ and $2$ in Figure P$4\mathrm{.}5\mathrm{.}4$ is $25$ psi, what will be the flow rate? The pipes are galvanized iron with $k_s=0\mathrm{.}0005ft.$ Take $v=1\mathrm{.}06{10}^{-5}f\frac{t^2}{s}$ and neglect minor losses.

Figure P$4\mathrm{.}5\mathrm{.}4$