Exercise $3.$ Pure $N{O}_2$ decomposes at $1000K$ according to following reaction:

$2N{O}_2(g)2NO(g)+O_2(g)$

The equilibrium constant $K_p$ of this reaction is $158.$ Analyses have shown that the partial pressure of $O_2$ is $0\mathrm{.}25$ atm at equilibrium. Calculate the pressure of $NO$ and $N{O}_2$ in the mixture at equilibrium. $P_{N{O}_2}=1\mathrm{.}99*{10}^{-2}(atm)$;$P_{NO}=0\mathrm{.}5(atm)$