The original pressure of the gas : 2.507 atm
Boyle's law and Gay Lussac's law
[tex]\tt \dfrac{P_1.V_1}{T_1}=\dfrac{P_2.V_2}{T_2}[/tex]
P1 = initial gas pressure (N/m² or Pa)
V1 = initial gas volume (m³)
P2 = final gas pressure
V2 = final gas volume
T1 = initial gas temperature (K)
T2 = final gas temperature
V₁=28 L
T₁=45+273=318 K
P₂=2 atm
V₂=34 L
T₂=35+273=308 K
then initial pressure :
[tex]\tt P_1=\dfrac{P_2.V_2.T_1}{V_1.T_2}\\\\P_1=\dfrac{2\times 34\times 318}{28\times 308}\\\\P_1=2.507~atm[/tex]