As a result of the constant volume batch reactor zero$-$order gas phase reaction A $->$ bB A $70\%$ and inert $30\%,$ the total pressure increased from $1$ atm to $1\mathrm{.}5$ atm for $2$ minutes. If the same reaction is performed in a constant pressure batch reactor under the conditions of $3$ atm and $40\%$ inert, what is the volume change rate $($V$/$Vo$)$ for $3$ minutes?