Answer
$45.99atm$
Work Step by Step
We can find the number of moles of oxygen as
$3.03kg\times \frac{1000g}{1Kg}\times \frac{1mol \space O_2}{32.00gO_2}=94.6874mol\space O_2$
We know that
$PV=nRT$
$P=\frac{nRT}{V}$
We plug in the known values to obtain:
$P=\frac{94.6875\times 0.08206\times 296}{50.0}=45.99atm$
