Answer
$587mm\space Hg$
Work Step by Step
We can determine the required pressure in $mm\space Hg$ as follows:
According to Boyle's law
$P_1V_1=P_2V_2$
This can be rearranged as follows:
$P_2=\frac{P_1V_1}{V_2}$
We plug in the known values to obtain:
$P_2=\frac{1atm\times 7.15L}{9.25L}$
This simplifies to:
$P_2=0.77297atm$
Now, this pressure in $mm\space Hg$ can be expressed as
$P_2=0.77297atm\times \frac{760mm\space Hg}{1atm}=587mm\space Hg$
