Use the Van der Waal equation to determine the pressure of 200 moles of CO2(g) in a 32.6L vessel at 34 degrees Celsius. (a= 3.64 L^2 atm mol^-2, b=0.04267 L mol^-1)

I got the answer 9.24 atm but the answer is 72.8 atm. I don't know what I did wrong.

did you use absolute temperature

(not Celsius)

are the units of your R value consistent with
the data you are using