A four stroke, $4-$liter gas engine operating on methane $($CH$4)$ at $3000$ RPM and $80\%$ volumetric efficiency delivers a brake power of $150$kW and generates the following emissions measured ona dry volumetric basis. CO$2$: $10\mathrm{.}4\%,$ CO: $1\mathrm{.}7\%,$ O$2$: $0\mathrm{.}9\%,$ NO: $600$ppm$,$ CH$4$: $1100$ppm$.$ Given the air density at ambient air is $1\mathrm{.}184$kg$/$m$^3.$

Calculate F$/$A ratio and the equivalence ratio.