A jet propelled engine having two jets and working on turbojet system has a velocity of $200$ m$/$s$,$ when flying an altitude of $12000$ m$,$ the density of air at this altitude being $0\mathrm{.}1725$ kg$/$m$^3.$ The resistance or drag of the plane is $650$kg$,$ and the propulsion, of the jets is $50\%,$ Given that the overall efficiency of the turbulant is $18\%,$ and the calorific value of the fuel used is $11750$ kcal$/$kg$,$ estimate $($i$)$ absolute velocity of the jet $($ii$)$ volume of air compressed$/$min $($iii$)$ diameter of the jet $($iv$)$ Power output of the unit $($v$)$ fuel consumption$/$thrust hp$-$hr and $($vi$)$ air$-$fuel ratio of the unit at the given altitude.