$($b$)$ For an aircraft $($data given below$)$ in LU flight at $(P_R{)}_{\text{m}\text{i}\text{n}\text{.}}.$ Find,

$($i$)$ Velocity $(V_x)$

$($ii$)$ 'ratio of zero$-$lif$-$drag to induced$-$drag'

$($iii$)$ Aerodynamic efficiency $($L$/$D$)$

The density at flight altitude is $p_x=8\mathrm{.}9068{10}^{-4}$ slugs $\frac{?}{f{t}^3}$

Aircraft Data:

Weight $=100,000lbs$

Wing Area $=1280f{t}^2$

$C_{D_0}=0\mathrm{.}018$

$K=0\mathrm{.}08$