Answer
$P=146.83kPa$
Work Step by Step
First we need to calculate the net force:
$F_{net}=F_{spring}+W_{piston}=150N+(3.2kg)*(9.81\frac{m}{s^2})=181.39N$
$A=35cm^2*(\frac{1m^2}{10000cm^2})=0.0035m^2$
Then the pressure inside the cylinder is:
$P=P_{atm}+\frac{F_{net}}{A}=95000Pa+\frac{181.39N}{0.0035m^2}=146.83kPa$
