Answer
$P_{2,gage}=96.92kPa$
Work Step by Step
$P_{2}=200kPa+100kPa=300kPa$
Knowing that:
$m_{1}=m_{2}$
$V_{1}=V_{2}$
$P_{2}=P_{1}\frac{T_{2}}{T_{1}}=\frac{300kPa*(300+273.15)K}{(600+273.15)K}=196.92kPa$
Then:
$P_{2,gage}=196.92kPa-100kPa=96.92kPa$
