A mixture initially contains A, B, and C in the following concentrations: [A] = 0.350 M , [B] = 0.900 M , and [C] = 0.350 M . The following reaction occurs and equilibrium is established: A+2B⇌C At equilibrium, [A] = 0.150 M and [C] = 0.550 M . Calculate the value of the equilibrium constant, Kc. Express your answer numerically.