The plot of $\log {\mathrm{k}}_{\mathrm{f}}$  versus $\frac{1}{\mathrm{T}}$for a reversible reaction $\mathrm{A}\left(\mathrm{g}\right)\rightleftharpoons \mathrm{P}\left(\mathrm{g}\right)$is shown.

Pre-exponential factors for the forward and backward reactions are ${10}^{15}{\mathrm{s}}^{-1}$  and ${10}^{11}{\mathrm{s}}^{-1},$  respectively. If the value of   for the reaction at 500 K is 6, the value of $\left|{\mathrm{logK}}_{\mathrm{b}}\right|$  at 250 K is ___.
[K = equilibrium constant of the reaction
${\mathrm{k}}_{\mathrm{f}}$  = rate constant of forward reaction
${\mathrm{k}}_{\mathrm{b}}$ = rate constant of backward reaction]