Consider the following single step reaction in gas phase at...

Consider the following single step reaction in gas phase at constant temperature. (2 $\mathrm{~A}_{(\mathrm{g})}+\mathrm{B}_{(\mathrm{g})} \rightarrow \mathrm{C}_{(\mathrm{g})}$) The initial rate of the reaction is recorded as (\mathrm{r}}_{1}) when the reaction starts with (1.5 \mathrm{~atm}) pressure of (\mathrm{A}$) and (0.7 \mathrm{~atm}) pressure of ($\mathrm{B}$). After some time, the rate (\mathrm{r}$}_{2}) is recorded when the pressure of ($\mathrm{C}$) becomes (0.5 $\mathrm{~atm}$). The ratio (\mathrm{r}}_{1}: \mathrm{r}}_{2}) is ______ ($\times$10^{-1}). (Nearest integer)