The balanced equation for the reaction is
CO(g) + 2H₂(g) ⇄ CH₃OH(g)
Since given concentrations are at equilibrium state, the expression for the equilibrium constant, k can be written as
k = [CH₃OH(g)] / [CO(g)] [H₂(g) ]²
By substitution,
k = 0.030 M / 0.020 M x (0.072 M)²
k = 289.35 M⁻²