$$ 37.8\,g\,N_2O_5$$ was taken in a  $$1\,L$$ reaction vessel and allowed to undergo the following reaction at 500 K  $$2N_2O_5(g) \rightleftharpoons 2N_2O_4(g) + O_2(g)$$ The total pressure at equilibrium was found to be  $$18.65\,$$bar.  Then, $$K_p = \underline{\hspace{2cm}}\times10^{-2}$$  [nearest integer]. Assume  $$N_2O_5$$  to behave ideally under these conditions. Given:  $$R=0.082\,bar\,L\,mol^{-1}K^{-1}$$