1 mole of each $\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}$ and $\mathrm{CH}_{3} \mathrm{CO}_{2} \mathrm{H}$ are allowed to react in I litre of solvent (dioxane), equilibrium is established when one-third of a mole of each of the reactants remains. What is the equilibrium constant K of the reaction at this state?