The formula of the saturated hydrocarbon in hydrocarbon$-N_2$ mixture was determined by burning a sample of the mixture with $30\%$ excess air. The combustion gases were analyzed and showed an Orsat analysis of $8\mathrm{.}95\%C{O}_2,0\mathrm{.}99\%CO,1\mathrm{.}99\%H_2,6\mathrm{.}46\%O_2,$ and $81\mathrm{.}61\%N_2.$ What is the formula of the hydrocarbon?