Answer
$0.058\,m^{3}$
Work Step by Step
According to Boyle's law,
$V=\frac{c}{P}$ where $c$ is the proportionality constant that depends on temperature and amount of gas.
$\implies c=VP=0.120\,m^{3}\times12\,kPa=1.44\,m^{3}kPa$
Since the temperature and the amount of gas is constant, we can use the value of $c$ obtained to get the volume at 25 kPa pressure.
$V=\frac{c}{P}=\frac{1.44\,m^{3}kPa}{25\,kPa}=0.058\,m^{3}$
