Catalyst A reduces the activation energy for a reaction by 10 kJ mol^$-$1 at 300 K. The ratio of rate constants, ${{{}^kT,\,Catalysed} \over {{}^kT,\,Uncatalysed}}$ is e^x. The value of x is ___________. [nearest integer]

[Assume that the pre-exponential factor is same in both the cases. Given R = 8.31 J K^$-$1 mol^$-$1]