The rate of all taxes levied by the State of Arkansas, not including county, city, and other local tax levies, in cities and incorporated towns whose corporate limits on March 11, 1957, extend to within one (1) mile of the corporate limits of an Arkansas city which adjoins a city in another state and is separated therefrom only by a state line, shall be at the rate at which the tax is levied and collected in the Arkansas city which adjoins a city in another state and is separated therefrom only by a state line.