The rate law of a reaction, $\mathrm{A}+\mathrm{B}\to$ product is rate $=\mathrm{K}{\left[\mathrm{A}\right]}^{\mathrm{n}}{\left[\mathrm{B}\right]}^{\mathrm{m}}$ on doubling the concentration of A and halving the concentration of B, the ratio of new rate to the earlier rate of reaction will be