For a reaction A(g) $\to$ products,           the following data are available.

Initial pressure of A, $p_{\mathrm{A}}/\text{ Torr }$   429              273                150

 Half-life period, $t_{1/2}/\mathrm{s}$               350            550                   1001

The rate of reaction at initial pressure of 500 Torr of A is