For the reaction, ${\mathrm{C}}_{\left(\mathrm{s}\right)}+{\mathrm{CO}}_{2\left(\mathrm{g}\right)}\rightleftharpoons 2{\mathrm{CO}}_{\left(\mathrm{g}\right)}$ the partial pressures of CO₂ and CO are 2.0 and 4.0 atm respectively at equilibrium. The K, for the reaction is: