The reaction: A$+2$B$->2$C is run in a gas phase isothermally in a PFR reactor.

A mixture containing $20\%($mol$)$ of A$,25\%($mol$)$ of B in an inert gas is injected in the reactor. Assuming that the reaction is first order in A and B and no pressure drop occurs in the reactor, write the stoichiometric table and the rate law for the reaction in terms of X$.$